How can I deal with the ordeal of my mother and brother being imprisoned, the refusal of relatives to help, and the gloating of neighbors, while maintaining hope and supplication?

You have done well in your eagerness to honor your mother, in your efforts to solve her problem, in not surrendering to despair, and in your abundance of supplication. Continue in this, for he who places his hope in Allah will not be disappointed, and patience in tribulation is one of the greatest means by which a person afflicted can seek help. Seek assistance from Allah, then from trustworthy and wise people, to prove your mother's innocence or to pay off the amount. If it is proven that your brother is the cause, then advise him and remind him of Allah and of the grave consequences of what he has done, especially his disobedience to his mother.