Unfortunately, I don't think that HRT will stabilize a scoliosis curve. It may possibly prevent future bone loss or stabilize your density but it will do nothing for scoliosis. The only way I know of to address scoliosis is with the Schroth method of PT. It's not a magic bullet and won't reverse the issue but it might help to slow progression slightly. It is difficult to find practitioners and most of the ones I have found don't take insurance but you can book a few sessions to learn the exercises and do them daily on your own (about a 30 minute commitment). The exercises are geared towards stretching, lengthening and breathing into the spinal curve for expansion in the opposite direction of your curve.

I've been on HRT for 7 years now, starting at age 62 after the completion of my Forteo regimen. Along with nutrition, weight training, walking, dancing, etc, I've maintained the bone density gain from Forteo. My curve is still my curve though.