On November 1, the late Christopher Reeve’s oldest son, Matthew, will be doing something he never imagined possible: running the NYC Marathon. “My father would probably wonder what happened to his son, who’s this imposter?” Matthew, 29, who will represent the Christopher & Dana Reeve Foundation in the race, tells In Touch. “Hopefully, he’d be impressed.” For those who knew his dad well, there’s no doubt. “Christopher would be so proud of his kids,” says his longtime friend Jane Seymour. “They’re doing what he asked us all to do.”

Indeed, after the 1995 accident that left him paralyzed from the neck down, Christopher was driven by two passions: his family and raising funds for research to reverse the effects of paralysis. “He couldn’t breathe by himself, couldn’t move. Yet he was able to make a huge difference globally,” Jane tells In Touch. “That’s why he’s my hero.” While he never walked again, others have. “It’s because of Chris,” says Jane.

For more on how Christopher’s legacy lives on five years after his death, check out this week’s issue of In Touch, on newsstands now.