Gmod Crash (Mac)

When ever I host a server and my friend joins, he just crashes (Mac), But my other friends join in without crashing (PC). And when he joins in again, he crashes right when I spawn in something (Like a weapon or prop). The server I host has a lot of addons which all of us installed. Is there any way my friend can fix this?

Tell your friend to verify integrity of game cache to do that right click on gmod click on properties click on local files then click on verify integrity of game cache that should get rid of anything crashing for him

He already tried that, it didn’t work. Any other suggestions?