Section 80DDB defines that an individual can claim a deduction for any expense incurred by them for a disabled relative. Whereas Section 80U defines that an individual, if certified as disabled, can claim a deduction under this section for any expenses incurred by him for his own treatment. Therefore, a parent can claim a deduction for the expenses incurred by them for the treatment of their disabled son under Section 80DDB and not under Section 80U.