shower seat

I'm putting in a new shower and I want a bench seat for my 80 yr old mother to sit while showering-the walls are granite-but the shower pan seems short with a center drain-then he built a bench seat that is outside the pan-I'm afraid this will not work-help!

Help with what? I have no idea what you are trying to describe. Maybe try again with more detail about how things were done and what was used to do them. There are many ways to build a shower bench.