Should we allow unstable Sister in our babies life?

RANT/ ADVICE PLEASE

RE POST FOR POLL .

I need some advice ladies . My sister in law unfortunately is an addict . She is addicted to speed and recently we believe she has started doing something harder as her teeth are deteriorating and she constantly has sores on her face . She lost her son a couple months ago for the second time due to neglect and an unsafe environment. Her animals are abused , she had a dog put down as she starved him and then my ML bought him dog food and while regaining his strength became , I don't want to say vicious but nasty towards her (obviously) After the dog was put down she got a new puppy , which has now been given to a shelter thank goodness , because she was losing chunks of hair (she asked someone to shoot the puppy first) She refuses to take any owner ship and is blaming everyone else . She refuses to believe she has a problem and it's everyone else who is delusional. My mother in law and especially father in law turn a blind eye and ignore her issues.

My husband and I do not have a relationship with her as we don't support her life choices or agree with how she mistreats people/ her children, animals and herself . We know she will use us , and lie to us as she has in the past and have made it very clear that unless she needs help getting sober she is not welcome in our lives . We have offered to pay for her treatment and hope that she decides to take it very soon .

My husband and I are in our second trimester and his Mom recently brought up his sister .... seeing and being involved with the baby . Personally I don't want her in our babies life . When we got home my husband said he just wants to make his family happy and let her just meet the baby and see her occasionally. I've never seen my sister in law sober. I don't want to cause any tension but at the same time I don't want to have to explain to our child who this shady person is they only see a couple times a year is as he/she grows . I'd almost rather explain to a child why Matante wasn't in their life then explain to a toddler why Matante looks like that , smells like that , why she walks like that .

I want her in our lives , but I want her healthy and sober in our lives .

Am I wrong ? How should I handle this ? Is it worth the fight ?