I would like to post a snarky but funny reply to show how ridiculous this is, bearing in mind that SIL, my brother, and their fam are very religious and I don’t want to start familial warfare.
Otherwise, I could post something pointing out how irresponsible it is for anyone to say that we are “worrying” too much about, you know, very real problems.
You are asking how to snarkily mock a meme with religious connotations without offending religious family members who posted this meme? I don’t think you can.
“I too pray for the President every day. I pray that he will die in agony when he and the Vice President are impaled by a piece of rebar intended for use in the border wall.”
Oh, that’s easly. Just rework this prayer for Joseph Stalin that is attributed to the Russian concert pianist Maria Yudina, said to have be sent by her in response to a monetary award she received from him:
“I thank you, Joseph Vissarionovich, for your aid. I will pray for you day and night, and ask the Lord to forgive you your great sins before the people and the country. The Lord is merciful and he will forgive you.”