Here's the setup:
My familiar is adjacent to the creature I want to target with my touch spell, and is within 100' of me.
Both the target and my familiar are around a corner, and I do not have a clear path to them.
I cast the touch spell on my turn, and my familiar uses its reaction to deliver the spell.
My familiar has a clear path to the target, but I don't. I think that's fine, and it all works. Does this function as I described?