Are the difficult circumstances that the questioner's family is experiencing—such as the husband's illness, frequent disputes and family problems, and repeated hospitalizations—due to usury, the evil eye and envy, sins, or injustice to someone? And what is the correct solution to these problems?

One cannot definitively pinpoint a specific cause for the aforementioned problem; it might be due to a sin. Usury (riba) is forbidden, and if there was no necessity, then you both must perform sincere repentance (tawbah (definition) nasuh) through remorse, seeking forgiveness, abandoning the act, and resolving never to return to it. You should turn to Allah Almighty through supplication, draw closer to Him through righteous deeds, and anticipate reward for the affliction. There is no harm in seeking ruqyah (definition) (Islamic exorcism/healing).