[Isura]

Since he limps every button I wouldn't c/r an A. If he raised sometimes, then I'd expect himi to raise Ax preflop almost always, except slowplayed AK/AQs. Thus if he doesn't have Ax in his pf range it's a good spot to c/r because he's calling with any pair, draw and we don't mind playing a slightly big pot.

But given he can have any 2, i think you maximize value by calling flop and letting him keep betting. Keep the pot size under control and let him keep bluffing. THere are basically NO scare cards to our hand, because of Ad and the dry board texture. Thus we're happy calling a normal bet on any turn. Our hand is also not vulnerable to free cards. If he checks turn then easy valuebet on the river. Probably around 1/2 pot to make sure any pair or K high calls.

As played, the 3-bet is very strong. I'd just fold to his 3-bet. He's representing a huge hand (you can't discount AK/AQ either since he always limps). Calling isn't terrible with the plan of folding on the turn, except the diamond. Since he bet so small I'd just take the odds and check/fold the river. Very unlikely he's folding a better hand on the turn and even more unlikely you get bluffed on the river.