Ideas for shower curtain modifications for extended tub seat

by Paula
(Columbia SC)

My father is looking for a tub seat.

He has an extended seat that was used for my mother while she was still at home.

But he does not want to use that seat because of the issues with the shower curtain not closing and water getting on the floor.

I would purchase an in-tub seat but feel that (1) he already has the transfer seat, and (2) his issues currently are standing for long periods but that may change.

Has anyone come up with a modification for the shower curtain?

He still lives at home so it will have to work without a lot of fussing on his part.

Thank you.