I think what the last episode showed about Jimmy is how inevitable his cycle of abuse is.

Ultimately, whether we have a supportive brother or one that wants us to fail, it's our responsibility how we respond to that.

Every time Jimmy feels insecure, his feelings hurt, or any other emotional issue, he goes on this bender where he hurts people.

This last one was most explicit, Kim says some harsh words to him on a phone call, and Jimmy goes scorched earth ruining lives.

This has been a perpetual cycle from the start of the show. Even the Davis & Main stint is him blowing it up because he feels like he doesn't quite belong.

Oh boo hoo my brother doesn't like me! You're a crybaby, who needs you?!