Is taking a loan from the bank for 2,0 euros and repaying 2,100 euros considered unlawful (haram), given that there is no other way to help the family in Lebanon, and the questioner's husband does not help them?

It is not permissible to borrow with usury to spend on a father or to give him money for a project, except in cases of extreme necessity. The husband is not obliged to spend on his wife's father. Rather, the maintenance of a poor father is incumbent upon all of his well-off children, male and female. It is not obligatory for someone who does not have anything in excess of his own needs.