She can take Becosules Z one tablet a day, Limcee 2 tablets a day, and
Vitamin D one sachet a week. It takes time to recover from the weakness, depending on the immunity different people take between few weeks to few months to recover. For your point on heart, you need to consider consulting a doctor, it is not prudent to suggest something on Q&A chat here. Also monitor her oxygen levels thrice a day, if it consistently dips below 96 consult a doctor.