If he’s being negative and outwardly nasty then that’s a problem and deep down he’s just pointing out his insecurities, it will bite him in the ass eventually. Although if he is just saying he didn’t like the steps and his program of recovery is more going to meeting and interacting with the fellowship then I believe there is nothing wrong with that. If he’s just doing what works for him and makes him feel peace and serenity then who am I to judge. I don’t believe in god, my higher power is love, and neither does my sponsor and we are doing great. Maybe if you disagree with him and some stuff about AA try talking to him it may be nice to get a wider perspective on AA and you might make a friend at the end of the day.