Why is he acting this way?

I recently met a guy M at a Meetup and we hung out in a big group. I liked him but I could tell his friend S was interested in me (I do not like S). A few days later I texted M about another get-together and added a smiley emoji to flirt. He said S was making plans and will let me know. The following Friday S texts me at 2pm and asks if I want to meet up with him and some of his friends to watch a basketball game at 7. I saw the text after getting out of work at 5 and didn’t have enough time to drive home and get ready, so I said “sorry I just your message and already made plans for tonight.” Then I asked him to let me know if he was doing anything else that weekend. He said sure but I never heard back. Two weeks later I see he’s going to another Meetup event. I join the event and S immediately joins right after me. Then right before the event starts M drops out! I still go to the event, S is there trying to talk to me. tried to make it clear that I was not interested – I avoided him, kept our conversations short, talked to everyone else except him, and left the event early.

Do you think M backed out because of S? Is there any chance M is still interested in me or has that ship sailed?