What about eliminating the door all together and just putting a pane of glass or maybe a glass block wall to cover one side. Leave the other side open for entry.

If it's just a standard tub, 60x30" in a small room, you probbably do not have enough space to turn a wheelchair around within the room and you will not have space for a wheelchair to enter and leave the shower. But you can probably make it accessible for someone using a walker. What are the overall dimensions of the room?

You will need to reinforce the framing so that you can install grab bars which must be mounted into studs in the wall. You'll want to place the shower controls where they can be reached easily from outside the shower.

I've never seen a bifold glass shower door. Usually the shower door is a single door that swings out. But it may be best for you to have no door at all. Even though the shower head may be at the other end of the shower, you can mount the controls elsewhere. You can purchase a copy of the National Kitchen and Bath Association's planning guidelines that include access standards. Look online at nkba.org.

Perhaps a shower curtain might provide a bit of flexibility when maneuvering inside the shower area.