Wow, knowing his history and understanding his need to belong and even to be looked up to, it is very difficult to advise you to deny that to him. On the other hand helping him feel important and even succeeding at this small level might be something to consider. You will not stop him from hanging out with this chevra. You can’t choose his friends for him at this stage, so how can you help him and guide him? Sabatoging his mission will not help either one of you, he will find a way to make it happen without your help. So what can you do to form some kind of alliance with him?
Again I would suggest some form of negotiation for the use of your personal computer. Make an agreement of some kind, either in regard to where he can use it or how he can use it. For instance, he can use it only if he asks you and only if he tells you what he is using it for, again explaining that it is just as important to you as his android is to him. Negotiate with him and come to an agreement.
Personally, in my humble opinion, I feel that it would be the best compromise and option. I dont see it as you helping him being a big shot with his friends, just as you and your son working an issue out together. Especially since he is not downloading anything to your computer and is just using it like an extension chord. But still I would suggest that you maintain an anti virus program because the files are being transferred through your computer, meaning your computer is reading them, therefore you must take very precaution to protect your computer.