The Three Wishes of Billy Grier is a 1984 American made-for-television drama film starring Ralph Macchio and directed by Corey Blechman.
While this movie is a fictional work, it is prefaced by a note accounting that a condition such as the main character's does exist, and that the film imagines the life of such a victim.
A team of doctors tell Billy and his mother Nancy (Betty Buckley) that there is no cure for his condition and that he will die of old age related natural causes decades before his time.
Billy finds the key to two of his wishes when he meets Phyllis (Season Hubley), a sassy young woman with dreams of her own, one of which is to open a beauty salon.
Billy helps Phyllis realize her own dream when she applies for a loan to open her beauty salon, introducing him (by the name Bill) as her friend and associate, when questioned about her business acumen.
However, the bank officer, after seeing Billy's obvious signs of aging, is convinced that he's a credible partner with experience, which minimizes the risk of giving Phyllis the loan, which is then approved.