40/80 JJJ. Can I fold? Please?

I would never fold here for two reasons: 1. there's a lot of money in that pot; and 2. If I were in his shoes, I'd play 88 or AJ in a similar fashion. And with approx. 11.5 BB in the pot, you don't have to win this too often to make a call correct.

I agree with previous comments that advise calling the turn, check-calling the river.