Re: DEBT
Valid attitude? I’d say not. because he shouldn’t have taken the money on interest in the first place. Now he must repay.
There is a hadith:
A man came asking rudely of Prophet Muhammad (pbuh) to return the debt. The sahabas got enraged because of the tone of the voice he adopted. Prophet Muhammad (pbuh) stopped them and said ‘He has the right to demand, even harshly’. Sahaba were ordered to buy a camel and give it to him as repayment. They argued that the camel they’re about to purchase is older and hence more valuable. So the Prophet Muhammad (pbuh) said, Give it to him, for you should return your debt handsomely. (Sahih Al-Bukhari: Hadith 2260)
http://www.sunnipath.com/library/Hadith/H0002P0046.aspx
Although, that doesn’t advocate paying interest. But you can see it is okay to repay a higher amount to show appreciation for the orignial favor.
Since this is a known interest deal that both parties were and usually are aware of, i’m sure. If muslim client decide to go interest-free or demand that, it would not be wrong of them either. Because the religion encourages to trade evenly. Don’t give interest, don’t take interest.
All the previous payments must be made as agreed upon though. Because a promise and a verbal contract was made. The damage’s already done. If the lender decides to give him a break for being in good business previously, and reduces the interest, that would be best. A compromise is best for both parties.