My father 53 year old were covid postive he was admitted in hospital for sever infection with 70-80 percent lung involvement, with the help of good doctors and god grace he is recovered and now on 2 litre oxygen, as doctor are giving discharge can we manage patient at home on oxygen concentrater and what criteria need to be followed to reduce patient oxygen from 2 litre to 1,-0 .when he will breath normal oxygen.