Better for you he's there and comfortabe having his friends over, than out somewhere doing whatever unbeknownst to you until possibly too late. You're obviously a good dad to extend this courtesy to him. I get to work with my oldest son thru the daily bill-paying jobs and the custom bikes too. I highly recommend it.
As we are in the construction field, we have tools for everything imaginable. We have tools to repair tools! We love tools. Can't seem to have enough. Always looking for more, new, and better ones!