How about a nice, “Yes, I will pray to Our Father for your loved one.”?
Responsibility2nd handled it quite nicely. While disagreeing on the dogma, added the prayer for the person at the end.
Love God more than you hate praying to saints.
The best way to teach Christianity is to show it.
I don't presume to know a whole bunch, but I know wrong and if his idea of praying to St Sparky is going to achieve his goal, oo rah! but please don't presume to know.
BTW I would think the best way to teach any belief is to live it, I think the Pharisees showed it by going out to the street corner to pray to be seen.
And I also recall some instruction on going into your closet to pray to God the Father.