What is the ruling regarding money that came to a father after his death, and are both the son who gave money with the intention of it being a loan to his brother and spent on the father's treatment, and the other son who gave money with the intention of treating the father, entitled to reclaim their money from this inheritance?

If the son and the elder brother paid money for the father's treatment as a donation or because it was obligatory for them due to the father's poverty, then they do not have the right to claim it from the inheritance. As for the money paid to the younger brother as a loan, they have the right to claim it from his private funds or from his share of the inheritance, unless he paid it on their behalf or as an agent. Providing for the father is among the greatest acts of devotion. As for the money that came to the father after his death, if it was a gift from the state to the heirs, it is divided according to the method specified by the state. If it was a pension, it is divided like an inheritance.