1 Player Crashes some Clients

Alright a good old friend of mine was recently joining my server and began crashing on Round Start (TTT). The reason this is an issue is because he takes several other clients with him. It doesn’t crash everyone just a few others. I know he doesn’t hack (he don’t know shit) and there is nothing wrong with the server. It only crashes when he gets on the server. I’ve had a solid 15 players on for a few hours and he gets on and he crashed taking 9 clients with him. I also crash sometimes. Anyone know what’s happening?

Note: Again it’s only when HE joins that the round starts and he crashes taking some others with him. Sometimes he takes me with him as well.

What addons do you have?

I remember this happening to me because I thought it would be funny to use obsolete as a trail material.
On equip anyone who could see it crashed to desktop :v:

Sorry for the late reply. I have the following addons on the server (Keep in mind I had the exact same addons before this was happening and he was fine. This just started yesterday.):
Damagelog_addon
GLMVS-master
pointshop-master
ps_subcategories
simpleweather (actually being removed right now)
TTT Spec DM
ulib
ulx

-Snip posted on his wrong double post-

Ask him to verify game files

I had an issue similar to this, something broke my PlayerInitalSpawn hook and sometimes players would spawn as player.mdl, and for some reason, spawning a ragdoll of player.mdl from portal 2 crashes anyone with it mounted.