One donk openraises to 20. I reraise to 60 with OTB.
SB, BB and Donk all calls.

Flop (240)
SB open pushes for his last 195, and if folds to me?

I guess it is an easy fold, but what hands would he do that with?
Are there a large portion of draws, or just sets or a flopped straight, being afraid of the flush?

SB is a good winner playing 23/8 and running at 36 ptbb over the 400 hands I have (small sample I know)

I'd say this is AK a lot of the time with AA/KK/99/TT some of the time and maybe something like Ac Qc, but you're pretty far behind to his range given that he cold-called a 3bet pf and then open-shoved into 3 players on that board. Fold.

Pretty easy fold...you're behind the range.

Yeah you have to let this go to the donk shove. Even if SB wasn't a tight player this would be a fold since even a donk range has you beaten severly. You only need 30% equity but this will be a K or better so often that I don't think you'll be able to call profitable. With his stats I don't even expect him to have [Qc] here (pretty much teh only hand you beat) very often if at all, AK seems by far most likely.