housing loan principal amount deduction.

1. Repayment of the principal portion is dealt in sec 80C(2)(xviii) which imposes only one condition under sec 80C(5)(iii) where the property referred to in the above section and repayment of principal was availed under this section then the property cannot be sold within a period of 5 years from the date of possession obtained by the assessee.
2. From the above reading, we can clearly see that there must be a possession of a house property u/s 80C(5)(iii) in order to fulfill the condition for claiming principal portion as deduction u/s 80C. 
3. Hence in your case client must have a house property in his name in order to claim the principal portion as a deduction. Deduction of the principal portion of the housing loan will not be available for your client. 
Please correct me if the above solution has an alternative view. 

Thank You Sir