He is 91 now but his neat grooming, mischievous blue eyes and mental sharpness belie his age.
Gerald is also enjoying a late twist to his life, as well as jokes at the expense of his "new" family, who inadvertently consigned him to history after a failed search to give him his share of a will.
It is obvious that for him there is compensation in borrowing from Mark Twain and explaining that reports of his demise were exaggerated.
"If life has taught me one thing," said Gerald yesterday at the old people's home in Wath-on-Dearne, South Yorkshire, where he lives, "it is that it never ceases presenting surprises. Still I have to admit at my time of life I haven't expected to be discovering relatives."
At the last count they added up to a surviving half-brother and half-sister as well as, through them, more than a dozen nieces and nephews spread around the country.
If anything the shock for their side of the Foster family has been all the greater because in the early 1970s Gerald was believed to have died.
Solicitors and researchers from the Salvation Army could find no trace of him and a share of an uncle's bequest was eventually split among others.
At the time, Gerald was living in retirement in Derby and the truth may never have emerged if his son Adrian hadn't begun looking into his family roots on the Internet.
He subscribed to Genes Reunited, an offshoot of Friends Reunited, and the country's largest genealogy site, with over 25 million people listed.
One of them turned out to be a late sister of Gerald with whom he'd lost contact after shunning the family's business in Guildford, Surrey, for a career of his own making.
He went to London and worked for a cinema company before moving to Derby and becoming a successful wholesaler in hardware.
Unknown to Gerald, his father remarried and had five more children, two of whom survived. One of them, David Foster, was traced by Adrian to Guildford, and a few days ago he brought the two half-brothers together in South Yorkshire.
"It was a remarkable occasion" said Adrian, a professional musician who lives near Wath. "I couldn't get a word in edgeways for more than three hours as the past spilled out.
"David is nearly 30 years younger than my dad but they had the same father so everything spread from that central link. Dad's background had already been something of a mystery to me. His mother died when he was a young boy and he was sent to boarding school. Later he was invited to join the family business but was too independent for that. It was a chapter of his life he didn't want to pursue. He made a life elsewhere and that was it.
"If it hadn't been for me he would never have known what had happened to his family. They tried to find him over the matter of the will but for some reason failed."
What about his share and can he now belatedly claim it? "We aren't talking about a fortune – a few hundred pounds as far as I know", said Adrian, "and anyway at 91 I don't think he's too bothered. People are more important than the money."