What should I say to my Hindi friend who has recently lost his mother?

I hope this isn’t a stupid question…

I have a fairly good friend whose mother has recently passed away. Normally I would write something about keeping him “in my prayers” or something along those lines, but I’m pseudo-agnostic anyway, and he is Hindi. I don’t want to say something generic like “I’m thinking of you…”, because he is a good friend, and I think it should be a bit more personal.

What does the collective think? Do you have any good quotes or lines about loving mothers? (BTW.. I didn’t know his mother.)

Thanks, all!