Though spot this guy has been raising preflop like a maniac.. 2x then 3x then 5x preflop HU!! He's just been raising so much postflop too.

min raise on button, he calls

flop: T78 flush draw

I bet half pot, he reraises min, I reraise 3x his reraise, he shoves all-in

Can you fold AA with flush blocker here ?

Because of his profile he can play any 2 cards so its a tough spot -_-

I'd call in that spot giving all the tells you are saying, he can definetely have a pair + draw or other things that are worst than AA even w/o the flush blocker (in most cases you are ahead, sometimes flipping and rare times under).

Also, if he is starting to raise really often that means his open raise is now wider (obviously) and his open-fold to 3bets all in gets narrower (because he wont call your all in with K2o, at least shouldn't) so if he opens lets say 80% of hands you can profitably 3bet all in a loooot of hands, actually you can solve it mathematically with icmizer or coffecalcs but even if you dont know the perfect strategy is good to know the theory basics (you can and should 3bet jam wider).