All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If you know that these clothes were stolen, then it is forbidden for you to take them and you should advise the person to give them back to their owners.
If he has no money, you should wait till he has the money; rather, it is desirable for you to renounce him from repaying this debt and consider it as charity. Allah Says (what means): {And if the debtor is in a hard time (has no money), then grant him time till it is easy for him to repay, but if you remit it by way of charity, that is better for you if you did but know).} [Quran 2:280]
Allah knows best.