Asking brother to give back lent money

I lent quite a lot of money to my brother two years ago as a help for purchasing a small house and an apartment for his family. We agreed he would return that money in one year, but he lost his job so he practically can’t do it. As I’m planning to move to Israel soon, I’d need that money for basic needs, as food and rent. My brother is not Jewish, I’ve made conversion, but it was done in Israel and by new law I can’t make aliya (by the way, many thanks for the answer I’ve got on that issue), so I have to make my living without any help as it is for new immigrants. 1. Am I allowed to demand my money back, or could I ask him to sell the apartment he actually doesn’t need, or how can I get the money in any way? 2. As an inflation rate is quite high here, we agreed also on interests for inflation rate, but he refuses to pay that, too. Is it against halacha to ask for those interests?

There is no prohibition against charging a gentile interest on a loan. One can insist that a loan- to a Jew or to a gentile- be repaid on time. One should however not do something that objectively may cause the feeling that Judaism demands of you less than normal family relations would have required of you had you not converted.