My father in law, at age 64, made his first hole in one, a momentous achievement. However, the hole he made it on normally plays about 130 from the white tees, but on this day, they had a temporary tee box set only about 80 yards from the hole. I'm guessing this still counts as a hole in one, but my question is, can this be disputed?

I'd give him credit for a hole in one.

I made an eagle once on a par 5 that had a temp green that was about 80 yards shorter than the normal yardage. I asked the pro at the golf shop and he said it was a legit eagle.
So I would say its a HOLE IN 1!!!

Doesn't matter what the yardage was....
He jarred it with his 1st shot....that sounds to me like a hole in 1!

Now for prizes and such I believe insurance companies need the hole to be min of 150 yards...but his ace is still an ace.

disputed by who?

I'd say take the card to a FedEx Kinkos and ask the guy at the desk what he thinks...I'd bet he tells your grandpa "you got a hole in one." And I've have to agree...tell him congrats for me and I'll be waiting for my beer via mail.