Live 1-3

Bttn straddles
Tag lady opens SB to $15 and has a $180 stack
Bad aggro Asian calls BB and has like $500
Hero in MP 3-bet to $60 w AdKd $850
Bttn who hasn't really gotten involved much, and has been seen limping K3s in EP, and who I was playing with at 2-5 earlier in the night 4-Bets to $150 and started hand with $650ish
Folds to Hero who ???

So, we are getting a really good price as his 4-bet is 2.5x, needing 1:3.58= 28% equity to continue, and we do have some depth. I think in general I would be continuing with my range as a flat, including KK and AA, maybe just 5-bet small AA exploitative-ly since I think he is pretty strong here. The guy in question is a traveling construction manager and he seems to play poker along his travels. I don't think he is knowledgeable of the game in general, but he was playing 2-5 with me earlier and seemed to not be limping too wide or shelling off a bunch of loose money. I think he is capable of having some AK here, but I do not know how often. I guess this is just a flat, but I did decide to fold to A) avoid variance and 2) possible some live players just dont have any bluffs here and im just getting super crushed vs KK+ range. After hand he says " I did not have AA..." 10 seconds pass. " I did have a blocker to the A and the K" lol. The fact he used blocker in his language makes me think folding was prob too tight, but he did take time to put that sentence together so it seems likely it may have been fabricated and he in fact had KK+. Any thoughts?