Oh my, still having the night sweats at 80, that's awful for you. Black cohosh did nothing for my sweats, I took sage, menopause supplements and they were all a waste of money and that's why I ended up on HRT patches. I still have night sweats, but I think they are down to what else is wrong with me. Maybe a wee blood check at your GP would do no harm to see if there is maybe something else going on that's giving you sweats. I'm sure you are exhausted most days getting so much disturbed sleep. I'm sorry I've no answer for you Nanascats some sail through the menopause with no symptoms and others, like yourself, it's never ending.
My friends mum has had cancer twice, she had to have a hysterectomy at 84 yrs old because of womb cancer. She gets night sweats and has herself convinced its because of the chemo she had years ago when she had breast cancer.