Denied, We will not accept that it was for anything other than to cause harm in the community. You would have no reason to spoof your steam id other than for malicious reasons ( intending or intended to do harm. ) You can appeal in a couple weeks when things have calmed down and you have decided if you want to actually be apart of this community. I also recommend you stop your brother from doing anything to do with your account because in the end you're still responsible for it.

I'm also pretty sure its not allowed as stated in Garry's Mod TOU

Denied, We will not accept that it was for anything other than to cause harm in the community. You would have no reason to spoof your steam id other than for malicious reasons ( intending or intended to do harm. ) You can appeal in a couple weeks when things have calmed down and you have decided if you want to actually be apart of this community. I also recommend you stop your brother from doing anything to do with your account because in the end you're still responsible for it. I'm also pretty sure its not allowed as stated in Garry's Mod TOU [quote]What you can’t do with Garry’s Mod Please don’t do any of these things (unless we’ve told you that you can, in writing) Distribute, hack of modify Garry’s Mod [all of it – the client, server, art, code] – unless it is to make legitimate mods, addons or content we mentioned in the first section of this page. do anything else we [or you] might consider naughty or illegal These could cause some real problems for Garry’s Mod and Facepunch – and I know you wouldn’t want that.[/quote]