MIL unable to get in the shower. What do we do next?

There are shower benches that fit inside a tub. There are also some that fit over the sides of the tub. The best option is for her to sit down on the chair part while outside of the tub, then lift one foot at a time over the tub while seated, and swivel to face the faucet and shower.

I got my mom a shower transfer bench since she has a tub with a high side. It has one part that hangs over the tub and suctions to the floor. The other part is in the tub and has a back. My mom's bathroom is very small, but with the help of her OT, she was shown how to sit on the bench and swing her legs inside the tub. I think the one we bought has a limit of 250 lbs.

The 'slide across' chair is great--tho I do think it has a weight rating and won't be safe if your LO is much more than 225 lbs. Please do check carefully!

The idea of cutting out a shower to accommodate a wheelchair is also good. Mother's shower has a very low lip on it, but it's all she can do to lift her foot 3". Pretty soon the lip will have to be removed--I don't know how YB is going to control the water flow----

Those 'walk in tubs' can cause a lot of hassle and do require a TON of hot water. A friend installed one for her mother, mother hated it and it always leaked a little....plus she had to be patient for the water to drain and she'd want to get out faster than the water was emptying. Then when her mother died, it cost her $2,000 to have the tub ripped out and redone as a regular shower. Said she should have bought a $20 shower chair instead of adding the sit-in-tub.

This was something I had to figure out when I brought my dad home (left side affected by stroke, right leg amputation below knee). Originally I used a lift and would lower him into a portable bathtub. However as time has progressed, he can not hold himself up well enough for that to be safe. I then started using disposable no rinse bathing wipes but it just wasn't enough. I recently found (quite reasonably priced on Amazon) an inflatable shower bathtub system for full body bed baths. This has been a life-saver! It has a water bag with a little shower head attached and it is easy to drain into a bucket. You place it under the person on the bed, inflate the sides, there's a little inflatable pillow for under their head, then use the bag to give a shower.

As Newbiewife said: transfer bench to life accoss.

Or sponge bath at the sink.

You could have her use a shower chair that extends outside the shower, sometimes called a transfer chair. The chairs have adjustable legs and you can get them in either right or left facing versions. They are readily available at pharmacies, Walmart, Bed Bath and Beyond, Amazon, etc. Just google "shower transfer chair." She can sit down on the chair and slide over into the shower while seated. She'd still have to lift her legs (or someone could lift them for her), but it's a lot easier than trying to lift the leg over while standing. Hopefully you already have grab bars in the shower, but if not, you should get them. She could do most of the shower sitting down, then stand using the grab bars so you could help her finish. If you don't already have a removable hand-held shower head it's an easy DIY retrofit to replace a fixed head with a hand-held one, which can also be used in fixed position. Those are readily available online or in local hardware or big box stores.

Try the no rinse products for now.    There are multiple varieties, but they are kind of expensive.    They're used not only in hospitals but in rehab centers as well.   Your MIL wouldn't have to undress completely, and in fact could be comfortably sitting in a chair with a nice warm blanket over her, sliding the blanket off only enough to allow someone to apply the products.

Then treat her with something special, a favorite CD, some safe fragrant body powder, cup of cider, tea or coffee, or better yet, something chocolate!