Please identify this book about a human turned into a god by aliens

I am wracking my brain trying to figure out the name of this sci- fi novel--and its respective author--that I read back in early to mid-1980s.

The book is about an ordinary man who, during some sort of interstellar space exploration (the book takes place pretty far into the future) is involved in some sort of accident or something and almost dies. He would've died had not an alien or aliens saved him. This alien (or aliens) is a god compared to humans and this man is given god-like powers too. Other than that, all I remember is that he saves three alien civilizations when their star goes supernova (or something like that). I wish I could remember more.

It was a paperback that I read, so I don't know if it was ever a hardcover or not. I don't know the title of the book or the author, unfortunately, but if someone told me I'd be able to say, yep that's it, or nope that's not it.

Thank you!!