Anyone been having crashes in coop?

My brother and I are having issues the last few days; he keeps crashing when we end turn. I don’t crash oddly. We have absolutely no idea what’s causing it.

We have many hours of coop together and this is a new issue.

He is Wulrik and I am Zhatan. We have tried various solutions but it keeps happening. Kinda feeling hopeless at this point? Thanks for any ideas