Topiramate and Phentermine for weight loss

I've used topiramate twice as a migraine preventive. Worked beautifully each time until I started losing feeling in my right arm -- that sort of numbness is a known side effect, but it's disturbing to experience. In both cases, getting off it was really hard. I had to taper very, very gradually, and the insomnia was terrible. Just one person's experience, but if you try this, I would encourage you to ramp up and down with care.

Basically, it's not a surprise that an anti-convulsant drug intended to target someone's neurology would have neurological side effects, right?

I have a two part comment/question:
The doctor had me taking Topiramate for years for avoidance of migraines. I had a Gastric Sleeve done in 2013. I lost 100 pounds afterwards; but since then have gained back about 45 pounds. I don't know if the Topiramate I have taken since about 2015 has helped with any weight reduction, but it doesn't seem to have had an effect. However, I cannot eat much due to my sleeve anyway.
I admit that over the years since my surgery, little-by-little I have begun to eat much less healthy foods. I also returned to eating sweets about 3-4 years post-surgery. (I've always had a big sweet tooth.) But whatever I eat, it is limited by the amount my sleeve can tolerate - which is not much.

I now am mostly confined to the bed; so I get very little exercise. I want to lose at least 30 of the gained pounds, but I really don't know how to do so in my current situation.

Now for the second half of my question/comment:

I have recently come to find out that my daughter-in-law (DL) , whom I dearly love, but who doesn't communicate well with me, has begun taking the prescription drug, "Phentermine" for weight loss. I am not sure my son even knows.

My DL is very overweight and has been ever since I have known her. She and my son were divorced a little more than a year ago and she went onto antidepressants. Since then, she has gained even more weight. I can understand why she would want to do something to try to lose the weight, but I am very, very concerned. My DL has had a long history of IV amphetamine drug abuse. She has been clean for 10 years (since she and my son have been together and she got pregnant with my granddaughter). I am very sure she has not told her physician about her dependency issues. She has custody of my little granddaughter. (Drugs caused her to lose custody of 3 previous children before my son.) Neither she, nor my son, take advice from me or my husband well at all. And I sure don't want to risk the ability to have contact with my little granddaughter; especially, if I need to make sure she remains safe.

I would like to know the thoughts from those of you who have experience in this area (professionally and personally) of how I should deal with this matter. Thank you!

@pattertp1 - wondering how things are going with your (former) daughter-in-law and taking phentermine?