Namo Mal said Kumar was the only son of his parents and, since his kidnapping, his father had not uttered a word except to ask about Kumar's whereabouts.
Namo Mal, also a close relative of Kumar, said his abduction had marred the happiness associated with Diwali.
The kidnapping of Hindu businessmen is not uncommon in Sindh.
There have also been many cases of Hindu girls being forced to convert and marry, a phenomenon that has caused concern to the community.
A majority of Pakistan's Hindu community live in southern Sindh province.
