Maybe he wants to be on Kendall's side on a personal level, but Kendall hasn't offered him anything substantial for his loyalty and even sort of fucked him over with the watch.

On the other side, he's both terrified of Logan AND got an actual offer from him.

I'm terrible at legalese, but signing for the joint defense agreement seems like it would be irreversible, so I think Grendall is over?

Kendall played that pretty badly, I think. The watch wouldn't have hurt his pockets much and would've solidified Greg as an ally. Then again I'm kind of unsure of how aware Kendall is of the cards Greg is holding at this point.