Grandmother, not my mother but mother in law?

He doesn’t like her one bit since forever. He try’s to hit her, push her away, when she kisses him he pushe she’d face with his elbow or slaps her.....

I’m trying really hard to stop this behavior (not hitting him when he hits her...because that just doesn’t make sense........right?)

My father in law has tried hunting many times that he just needs a good smack on his butt.

I really am against hitting him unless he puts himself in danger, such as grabbing bleach bottles in grandmas house, running towards a road, etc

Has anyone gone yhrough this?

Is this a phase?