LOL. Yeah.

More logically, it depends what you hit. You could get shot 5 times, and if it mainly hits muscle and non-vital organs, live through it.

But if you get shot once right through the heart, you're done for (especially in 1951).

Also, and this is a quibble, I don't think Vito ever returns to full strength afterward. He is in bed for months, gets on his feet when Sonny gets killed, but clearly is still not in very good shape.

Then after Michael returns and comes to get Kay back, he tells her, "my father's been sick ... very sick."

According to the DVD timeline of when Vito was supposed to be born, he was barely 60 years old or maybe not even 60 when he died - and he sure wasn't in very good shape for 60.

He did recover somewhat but I don't think he ever made it back to "full health" or anything close to it.