Live 1-3
Very big whale limps HJ and has around $200
CO decent reg opens $15 and has $300
folds to hero on the BB w AJo $300 effective

Im not really sure what the bottom of my flatting range should be here facing a 5x open. I think I am incentivized to flat a little wider here with the presence of a whale. I would for sure fold things like ATo, KJo, QJo,A2s-A8s(maybe 3b A5/A4s), maybe start flatting somewhere around A9s-AQs, JTs, QJs, KJs, KQs, and then use something like QTs/KTs/T9s, AKs and TT+ as a 3b. I might even flat AKo/AKs sometimes to keep the whale in play.

Generally tho, im just not sure if AJo and KQo are strong enough to flat a 5x raise to play OOP 3way with a competent player in the pot. I do think he is isolating about normal(may be a bit wider than what you would see online, as i think its normal for live regs to isolate a little more aggressively with the absence of 3betting in most games)