Run the other way! If you don't there are two choices for you: 1) It will get worse. 2) She will need to be so doped-up there will be falls and other side-effects. I guess a third choice is that both will happen. Life doesn't get better it only gets worse :( Sorry for the negative post but I've been dealing with my mom's depression for many years now and it's about ruined my life (and now I'm depressed!)
My father has never dealt with depression in his life, that I’m aware of anyway. But in the last year as his physical capabilities have continued to diminish and he’s experienced continued loss of friends and family members he’s most certainly been more down and negative. His doctor recently added Zoloft to his meds. We’ve not seen any miracle but definitely a more positive and encouraged person. I can’t recommend it in your situation as I don’t know enough about it, but a conversation with mom’s doctor is certainly needed as a first step
Thank you for reaching out for support.
I think you may find this article helpful: https://www.agingcare.com/articles/elderly-depression-warning-signs-to-look-for-110498.htm