Steam account question

So, my little brother just got a copy of Half Life 2 for his birthday. Problem is, his computer can’t run the game, so it’s probably going to get installed on my computer or my mom’s computer. If I install the game on my Steam Account, can I transfer it to him at a later date (like, if I move out of my parents house again), or would I pretty much need to buy him another copy of the game for him to play it after I left?

Actually, this question also applies to my room mate’s copy of Half Life, which I ended up registering to my Steam account when he loaned the game to me (which wasn’t an issue for him, since he got a new version of Half Life with his copy of Half Life 2). In any case, the game DOES belong to my room mate, and he wants his CDs back. Will he (or anyone he gives them to later) be able to use them if the CDKeys are registered to my Steam account?

The game belongs to the account, there is no transferring. Why not just create an account for your brother? Use it on your computer until you leave then let him use it.

For your room mate, if you installed it on your account, the key will only work on your account. He could use the CDs to install the program, but only with a different key. If you don’t want to give your account to him he’s out of luck unless you buy him another copy.

Thanks for the answers, yoyodyne. Turns out the Steam website has the answers to these questions too, a new CD key for the old games can be got for $10. In any case, my room mate and I worked it out (he’s just gonna let me keep his copy of Half Life since he got all the old games with his copy of HL2)