Matthew 26:39-44New American Bible (Revised Edition) (NABRE)
39 He advanced a little and fell prostrate in prayer, saying, “My Father,[a] if it is possible, let this cup pass from me; yet, not as I will, but as you will.” 40 When he returned to his disciples he found them asleep. He said to Peter, “So you could not keep watch with me for one hour? 41 Watch and pray that you may not undergo the test. The spirit is willing, but the flesh is weak.” 42 [c]Withdrawing a second time, he prayed again, “My Father, if it is not possible that this cup pass without my drinking it, your will be done!” 43 Then he returned once more and found them asleep, for they could not keep their eyes open. 44 He left them and withdrew again and prayed a third time, saying the same thing again.
Jesus prayed the same thing three times. He must not have been a good Christian.
Seriously though, all you can do is gently share information with him. He might just come up with another critique to insult the faith. In my mind, he isn’t being fair by criticizing things he does not understand and is not being kind by criticizing your religion. Pray for him.
Matthew 6:9-13New American Bible (Revised Edition) (NABRE)
The Lord’s Prayer. 9 [a]“This is how you are to pray:
Our Father in heaven,
hallowed be your name,
10 your kingdom come,[c]
your will be done,
on earth as in heaven.
11 [d]Give us today our daily bread;
12 and forgive us our debts,[e]
as we forgive our debtors;
13 and do not subject us to the final test,[f]
but deliver us from the evil one.
You’ll note that in verse 9 that Jesus said, “9 This is how you are to pray”. Jesus literally told us to pray that way. Often, I use the Lord’s prayer as a way to worship. I start with the words in the prayer and then venture off with my own prayers so that I have a full understanding of what it is I’m claiming in the Our Father. I’m using a formulaic prayer and expanding on it and contemplating what it means. I’ve been doing this for years and it makes sure I know what I’m asking and saying. Those words have real meaning for me and a lot of it is probably because of this exercise.