My guess is that during a conversation with Wendy,Abel will say something like "Why did grandma hurt my mommy"? or something along those lines and that is how the truth will come out.
I'm still thinking that Jax and Wendy wind up getting together to raise the boys.

Gemma is really starting to go full on batshit. I don't think I was the only one expecting to see a murder in the cabin.

I also think that Jax survives the series,only because everybody
is expecting him not to. Sutter is a fantastic writer and a cunning weasel,so we are in for some of the best TV ever made during these final episodes.