Samuel Campbell, 24, died from a single knife wound to the chest during a "scuffle" with his sibling William at their mother's home in Sunderland in June.
Newcastle Crown Court heard the brothers, who were like "chalk and cheese" had been in the garden, where Samuel had been drinking Bourbon and listening to music by the fire pit with the dog Marley.
Campbell, who "disapproved" of bar worker Samuel's lack of full-time employment and his reliance on their mother to walk the dog, had just returned from a night with a friend, who he had shared 25 shots of vodka with.
The fatal argument started after Campbell claimed his brother had been "raising his voice to the dog" and wanted him to apologise.
Their mother Carolyn Campbell, who had been in bed at the house, had gone downstairs to tell her sons to be quiet so as not to disturb the neighbours after she heard them arguing.
But the court heard the trouble continued and Campbell, now 26, picked up a knife from the kitchen and stabbed his younger brother in the chest in the garden.
William Campbell, 26, of Allen Court, Stokesley, North Yorkshire, denied murder but was found guilty by a jury after a trial at Newcastle Crown Court last year.
Judge Paul Sloan QC sentenced him to life behind bars and said he must serve at least 21 years before he can apply for parole.
Carolyn Campbell, who had already lost one son in a car accident, did not make a formal victim impact statement at today's sentence hearing but prepared a document herself, which was not read out or made public.
Their father Eddie Campbell, who did not live with the family, made a statement, which was referred to by Nicholas Lumley QC, who defended Campbell.
Mr Campbell Snr said in the statement he felt "shock and disbelief" at what happened and the verdict that followed and added: "William admitted the only thing keeping him alive is the love and support of his family. We love William and Samuel equally and that will never change.
"William and Samuel grew up extremely close to each other and with their cousins and the loss of both of them has affected the whole family immensely."
Mr Campbell said a "void" has been created by the loss of both brothers and family members "would like to see William free again in their lifetime".
Samuel's long-term partner Alice Gray fought back tears as she read her statement from the witness box.
She told the court Samuel's death has had a "catastrophic affect" on her and "utterly devastated my life and broken my heart beyond anything I knew possible".
She added: "The fact I have to live on without the amazing, gentle, kind man by my side is overwhelming.
"Sam was the love of my life and best friend. He left this world in such a violent and horrible way.
"I am existing from day to day. I will never forget hearing the news. At first it was total shock, I couldn't understand Sam wasn't coming back.
"The majority of his friends found out through social media, before I could reach them."
Miss Gray, who is a teacher, said the stress and trauma caused her to develop a medical condition which means she completely loses her voice for periods of time, which could threaten her career and cost her her home.
She added: "I wake up each day missing Sam and a horrendous numb, void feeling.
"I find myself driving to Sam's grave in the middle of the night, just to be beside him. I visit his grave every day."
Miss Gray said her chance to start a family and for Samuel to become a dad has been "ripped away from us both".
She added that she hopes she "never comes face to face" with Samuel's killer again and added: "Your actions have taken me to hell and back and will stay with me forever."
Judge Sloan said: "It would seem you took exception to the way your brother had been talking to his dog.
"The dog had been a source of conflict between you for some time."
The judge added: "The argument had been over something totally insignificant but in your drunken state you became frustrated and got it into your head youhad a score to settle with your brother."
Judge Sloan said Campbell had done "all in your power" to evade criminal responsibility for his brother's death by claiming self defence, lack of intent and diminished responsibility during the trial but told him: "The jury saw through your lies.
"I have considered the statement written by Mrs Campbell. It is a short statement in which she asserts no words could begin to express the impact youractions have had upon both her and the rest of the family but as your mother she pleads for such leniency as the law will permit."
The judge added: "The stabbing occurred in the presence of your mother, she having already lost one son following a road traffic accident.
"It occurred notwithstanding her repeated intervention and her attempts at peacekeeping.
"You will have to live the rest of your life in the knowledge you murdered him.
"I have no doubt you bitterly regret your actions that night and I take that into account."
Prosecutor Toby Hedworth QC had told the court on the night of the killing Carolyn Campbell had already broken up a "scuffle" between the brothers insidethe house and added: "Samuel said something, according to his mother and went back outside with the dog.
"The defendant sat down on the sofa and said he had just told his brother not to talk to the dog in the way he was doing.
"Then, his mother noted the defendant got a bit frustrated and said 'I'm not having this'. He said 'I'm getting a knife'.
"He went into the kitchen.
"Mrs Campbell didn't follow him in there but did go out into the garden and recalls trying to get between the sons.
"There was, as she subsequently described, a bit of a scuffle.
"Samuel then took off the hoodie he was wearing and saw blood on his chest.
"At some stage their mother recalls Samuel egging his brother on and saying 'you've stabbed me' then Samuel collapsed."
Campbell told a police officer at the scene "I stabbed him out of rage" and later claimed "I deserve to die".
He told jurors from the witness box during the trial he was "absolutely devastated" by what happened and said "it started because he was raising his voice to the dog."
He added: "It was just the way he was talking to the dog, the way he was being, I only wanted the situation to simmer down and diffuse.
"My only intention was to go out and apologise to our Sam and I wanted him to apologise to the dog and myself also."
The court heard Samuel still lived at the family home with their mother, whereas his older brother had moved out and lived in North Yorkshire for work but was visiting for a few days.
Mr Lumley said it was a "highly unusual and sad case" and said Campbell has completed courses in prison, where he is a trusted mentor who advises others.
Mr Lumley asked the judge for "justice for Sam but also to be lenient enough to William to allow him a life after this period".