a not so hypothetical

[jba]

say it folds to you in the cutoff and the button and blinds are stupid tight so you raise with some really trashy trash. the super-nitty button 3bets - this means either JJ+ or QQ+, decent chance of AKs, and maybe AKo (but highly doubtful). and the blinds fold and it's on you.

after some conversation he offers to give you .5 sb back if you fold. at what point do you accept his offer?