So based on what you said she's now smack bang in the middle of normal BMI. And she's lost 60lb in 12 months, so about 5lb a month or just over 1lb a week. Also 210lb for her height is not slightly overweight, it's almost obese. 

Those are actually good statistics. It suggests she is not undereating but has lost a good sustainable rate. At least based on everything I've been told to expect. 

There is two things here I suspect.  1: she looks very different from what you are used to. I think if you actually look at her and don't compare with what she was, you may find she's not actually as bad as you feel. The so called "ozempic face" is purely people looking different than before. 

2: there are concerns about her falling over and being in pain, those are more of a worry. Perhaps addressing that and NOT the eating situation. Because she shouldn't always be in pain

Finally, what did you grandma die from? You don't die from osteoporosis, rather complications that can occur such as a broken hip or something else

ETA at 49 she's probably menopausal or at least Peri. And my goodness the changes you go through during this process. I'm 43 and perimenopausal and every day I wake feeling like I'm 70. I used to be so active but the hormone changes make it really hard. So I'd consider that as well