I think you do the best you can, being as helpful as you feel comfortable, interacting with this teenager and don't take him too seriously. You are an adult, so I would not take bf's advice necessarily either, would accept his opinions/desires are his but take issue with how he spoke to you. You are your own person in relation to everyone you are in contact with, your bf does not "own" his son nor you any more than his son's ideas/desires of what your bf should do are more than his ideas/desires. I would not be "hurt" by anyone asking but not taking my advice or making stuff up about me (especially a teen/child) or whatever. If you do feel hurt by the son, I would not give him any more advice? Sounds like he does not want it?