How is justice achieved in providing financial maintenance for children when there is an age difference between them?

Question:
I ask Allah to do you good, Honorable Shaykh. This questioner says: I have two sons. One is twenty-two years old and is studying at the university, and the other is in high school and is seventeen years old. The younger one receives a stipend of about seven hundred riyals, while the older one has no stipend or income. He is studying in Riyadh and lives in an apartment. The question is that my younger son says: "You must provide for me just as you provide for my older brother, despite the age difference and the circumstances that require different support for each of them." So how should the maintenance be provided for these two sons?

Answer:
Maintenance is provided according to need. You provide for each one according to his need, and some may have a greater need than others. It is not necessary to make the maintenance equal between them; rather, you provide for each one according to his need. There is no doubt that maintenance for a child is not like maintenance for an older person; maintenance for the older person is greater. So you provide for each one according to his need, and this is justice in maintenance. And Allah the Exalted knows best, and may Allah send prayers and peace upon our Prophet Muhammad and upon his family and all his Companions.