Only One Map Wiill Load

Hello, my friend has been having an issue lately with getting on Garry’s Mod and loading maps. As described by him, whenever he gets on any server, the only map that will successfully load for him without him crashing entirely is rp_c18_v1. Attached below is exactly what he said his problem is via Steam chat, and his SteamID as well if anyone has any direct suggestions towards him.

His SteamID is: STEAM_0:0:29550371

Any help/replies on here will be greatly appreciated. I will be sending my friend both this thread, and responding on his behalf if needed.

First thing he should try is removing any addons including workshop ones

He will even crash or gm_flatgrass and construct?