Hair fall problem. Fall pls do help.

My sister 32 year old is suffering from hair fall and day by day it is just increasing if she just run her hands on hair she gets bunch of hair in her hand even her scalp  is visible little. Her hair fal problem is getting worse actually. I am just mentioning her routine she wash her hair twice a week , she applies hair oil ( coconut oil  any oil with vitamine e in it) before she wash hair. Before she used to dry and  straighten her hair at home with her hair straightener frequently. She don't have any medical issue . Recently she has been recovered from COVID19 she got corona positive in November end and got fully recovered in December. Now she is totally fine but what will be the issue for her hair fall pls do help.