All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is permissible for you to ask your brother to give you back your loan since he is not in financial difficulties. Contrarily, he should take the initiative to give you back your debts himself without urging you to ask for it because the procrastination of a rich person is an injustice as per a Saheeh Hadeeth. Procrastination is delaying what is due without any sound reason.
However, we have already clarified in Fatwa 128088 that it is permissible for a creditor to ask his debtor to pay back his debts if he is well-off and this does not decrease his (the creditor’s) reward.
Allaah Knows best.