What do I do when my 93 yr old Father makes sexual comments to me?

I'm going out on a limb and assuming he's suffering from some kind of dementia--in which case, all you can do is gently hush him and remind him "that's not how we talk, dad". If he's OK, mentally, you get a little tougher with him. If he's talking that way to you, what's he saying to other women?

Is this a constant thing, or just out of the blue? Makes it harder to take him places, I imagine.

Come back with more details and you'll get better answers.