I have a map where the player picks up Wheatley, but they can through him into goo as soon as they pick him up. This causes many problems for the map, so I was wondering if there was any way to make it so you can't drop him, like in the campaign. Thanks in advance.

You can, if he's an npc_personality_core. I believe DisablePickup stops any form of +use, although I may be wrong.

Nope. You can still drop him, but then you can't pick him up. I have a system set up were "OnPlayerDrop->!Self->ForcePickup" Its working so far, but if you spam use and move, Wheatley likes to jerk around. I can work with this, but if anyone happens to find a more efficient way, please let me know. Thanks for your help.

decompile a game map, see how they've done it there

Maybe they put something in front of the player to stop +use from working?

i thought maybe that they put an input like onpickup setparent !player