Only God can say whether he is. It's not "judgmental" for any of us to express the desire that the pastor honors God through his words and deeds as he attends this Satan-glorifying festival.
It somewhat reminds me of John who wanted to stop a non-disciple from preaching--
John said to him, "Teacher, we saw a man casting out demons in your name, and we forbade him, because he was not following us." 39 But Jesus said, "Do not forbid him; for no one who does a mighty work in my name will be able soon after to speak evil of me. 40 For he that is not against us is for us. 41 For truly, I say to you, whoever gives you a cup of water to drink because you bear the name of Christ, will by no means lose his reward.
Mark 9:38-41