Deduction under section 80ddb

Law says deduction will be allowed to himself and family members who are dependent on him.
So as per law a person mostly dependent on one person.
So firstly you have to see whather your close relative is dependent on you or not.
2ndly close relative should be your brother, sister, spouse, children and parents.
3rdly if you able to proof expenditure made for medical treatments spend by both of you and patient are dependent on both of you.
Than In order to claim this deduction, however, you will have to submit Form 10-1 from a specialist doctor confirming the treatment of the disease.
Otherwise only one person can claim.