Ex-Gratia amount quey

Dear Experts !

Is ,

a) Ex-Gratia amount paid by employer to an employee is fully taxable ?

b) Ex-Gratia paid by employer to employee on injury during active service or to his family on death during active service is fully exempted 

c) Any amount paid by an employer to an employee for treatment of COVID-19 is fully exempted or their is any limit ?

d) Any amount paid by any person as help to a COVID-19 patient for treatment or to patient's family on his death is fully Exempted upto 10 lacs in the hands of patient & his family ? 

Thanks & Regards