My mom now hates my friend what can I do?

Well my ex bestfriend recently decided that the plans we had for the summer(That we had scheduled since October) Decided I wasn't good enough. After me spending all my money on gear for this trip(It was a mountain hiking trip) I forgave him but I know now where my loyalties lie. But my mom now hates him because of this, Now my mom used to legit love this kid she took him in when he got into fights with his parents paid for my friends depression medicine and a whole bunch of stuff. So now what can I do? Should I stay neutral or side with my mom? I would never side with him because I don't think its right to go against your mother or father.