Is it wrong for my husband to speak up and tell his 84-year-old mother that she is being incredibly inconsiderate with her laziness and filth?

My 84 year old mother in law has become so incredibly lazy, that she no longer does anything to help herself (let alone anyone else). She gets out of bed in the morning, fills her pockets with Lil Debby cakes, cookies, or whatever, and sits down in her chair ALL DAY LONG and does absolutely nothing! She does NOT even get up to walk to the bathroom to use the toilet! Per my husbands request, at 5:15pm, I am to fix a plate of dinner for her. I physically walk it down to her living area of the house, walk over to where she sits, and I hand her her a plate of dinner, where she eats. My husband comes home from work a 6pm. Before he even says hello to me, he walks down the path outside to her door to tell her it is time for her to take her shower. Sometimes she comes up on the 1st request, but many times she won't come until the 2nd or 3rd request. After she does manage to get up, she has a HUGE mess of poop and pee all down her backside and down her legs! She gets into the bathroom, with all that mess, and sometimes really takes a shower, and sometimes just splashes around and pretends. All the while leaving a NASTY bathroom for us to clean, as well as everything she has touched on the way! She will then try to get back to her room before we can see if she really is clean, or IF she has put a clean diaper on. We have to be sure she gets her diaper on, because- like I said, she is so lazy, she won't do it. After all that, she goes back to her room, watches tv, and goes to bed. HERE IS THE PROBLEM; The following morning, this whole scenario starts over! I am so sick of this! She has been living here for 22 YEARS! Back then, her doctor thought she 'may' have early dementia, which she latched onto and played every time it was convenient. Other than her laziness, we haven't seen any "dementia" as we know of dementia. I was in the medical field, my grandfather and grandmother HAD dementia, so I am very familiar with dementia. THIS is pure laziness! If she can walk, talk, answer questions, know her name, knows who we are, who her grandchildren are, knows where to go when we tell her to go to the bathroom, knows how to eat and knows what she wants- THEN DAMN IT- is it too much that I tell my husband that we should put our foot down and tell her she is being inconsiderate and down right lazy by not doing things for herself that she should be doing? She is a complete narcissist at this point! Not even caring just a little about our lives as a family! This is beyond disgusting! My husband doesn't want his mother to feel bad- or feel as if she is a burden. DAMN! How about her NOT being a burden! I am so sick of this filthy pig of a human being!