Breast cancer survivors: How long was it before you regained your strength and energy after completing treatments?

My mom was diagnosed with stage 1 four years ago (no family history of breast cancer). She completed the treatments 2 and a half years ago, but she still doesn't fully have her strength and energy back. She did 6 rounds of chemo, 33 rounds of radiation, and 26 rounds of herceptin. She decided not to take the cancer pill because of the side effects.

She suffered an ankle injury 3 months before completing the treatments and has been immobile ever since. No surgery was needed on the ankle.

She rarely exercises and doesn't consult any dietitians/nutritionists and doesn't know what to eat and what to avoid eating. She planned on doing physical therapy, but Covid forced her to wait and she hasn't left the house since Covid started.

When will she get her strength and energy back and how can she regain her strength and energy? I've had to hit the pause button on my life and both me and my mom want our lives back. I want to have a life again and not be stuck in the nest caregiving.

Side note: Her oncologist died last month, so she can't contact her.