Stinks of AA or KK to me, he is never folding on the flop, prob sigh shove hoping he has AK at best, he probably just jams AK pre.
Folding may seem weak, but I see this so often, he obviously wants the shove or call, he is never going to fold whatever the flop is, go with your gut.
Folding still leaves you with a decent shove stack, I think you will need to hit your set though if you call.