بسم الله الرحمن الرحيم
It is haram to receive interest by depositing the amount in the bank and it is makrooh to deposit with this intention. However, if it is deposited with the intention and purpose of security then it shall be lawful to deposit but it shall be haram to consume the interest for himself. The amount of interest should be given in charity to the poor and needy ones without the intention of reward.
If your uncle is handicapped, he may invest money in some business if it is possible with the advice of some pious man.
Allah knows Best!
Darul Uloom Deoband