Witnessing grandmother with severe Myositis peeing in jars in her kitchen and I am absolutely horrified. Any suggestions?

Disney, it's a bit confusing - how can somebody who is "nearly paralyzed" manage cooking and laundry "very well"?

You say there is a visiting care agency, that's good. And then apart from you, what other family members regularly visit and help your grandparents? Have you talked about this to any of them?

I cheerfully admit I'd never heard of myositis, but we learn something new every day! This link - https://www.myositis.org/patient-support/living-with-myositis/ - is from The Myositis Association and may be helpful if you haven't come across it before.

I think my grandfather knows about her doing this (we were not supposed to tell him because again he can be easily agitated) but I think he’s afraid to tell her about it. She has Myositis and is in a power chair but can go shopping and do other things like cooking and doing the laundry very well (she sometimes has to have help like getting things out of the cabinet and doing dishes which is where I help when I’m at their house). Her wine bottle is stored under the kitchen sink (my grandpa obviously knows about that and currently does not have any issues regarding her drinking) but she only has it when she wants to and she’s not an accessive drinker. I think if there is a problem, she and my grandfather would tell the family but I don’t see anything wrong right now (I’m only 20 so I’m not a caretaker so to speak).

So someone helps her get up and dressed 3 times a week (I'll assume they help her shower then as well), what about the other 11 times each week she needs to get dressed/undressed? And it's hardly any more difficult to swap our a pad than to pee in a jar, so that doesn't really hold water - do you think she is demontrating a lack of cognitive function or is she simply inured to her behaviour?

Who is cooking the meals? Cleaning the house? Doing the laundry? Is everything on your grandfather's shoulders?

You say she is "nearly paralyzed" but what does that mean? Can she walk, or is she in a wheelchair?
And where is the wine coming from, since from what you describe she couldn't possibly be going out shopping on her own?

She sometimes wears Depends but I don’t think she will use them (she would have to change them a lot which would be VERY hard for her since she is nearly paralyzed). She does have someone (Visiting Angels) come to the house I think at least 3 times a week to help her get out of bed and dressed but she can eat very well. I’m also concerned about whether she’s becoming an alcoholic because she drinks wine a lot

If the problem is that she can't get to the bathroom due to mobility problems then there are urinals designed for women, she could use a commode placed where she can get to it easily or she could wear an incontinence pad, pull up or brief. I've got to say though that this is likely just the tip of the iceberg and most noticeable of her needs, how does she handle all her other ADL's -eating, dressing, bathing?