Is 80-85 spo2 ok for post covid patient?

Is 80-85 spo2 ok for post covid patient? It’s been more than 3mnths since my mother got discharged from icu… Still her spo2 is between 80-85 and she’s not breathless…
For how long do we’ve to keep her on supplemental o2? Please guide me into this

You can Try PIRFENEX 200 mg TDS