What is the ruling on taking money from brothers and sisters, and must it be returned, knowing that one does not possess money, and does the same ruling apply to money given on Eids?

The default rule is the permissibility of taking money from siblings and relatives if it is with their consent and from a lawful source, provided it is not a gift of recompense (in exchange for a benefit). There is no obligation to repay money taken if it was a pure gift. It is commendable to reward them as much as possible.