He changed my life. Twice.
The Doctor saved his whole family, rescuing his grandmother from an alien, his mother from his father, and his father from hate.
Saved him too, thanks to the Doctor's companion who had sent him after his father, chasing down reconciliation. Together, the pair taught him freedom, love, and most importantly, forgiveness. His mother, though, did change their family name. She forgave his father, but wouldn't allow him to return.
The alien taught him ingenuity and to not be greedy.
When he had grown and had his own family and son, he did his best to instill in Elton all the lessons the Doctor had taught him. After all, they were what had attracted his wife to him.
Tommy never expected to see the Doctor again.
Especially not the night his wife died.