I have a younger brother. He talked about a girlfriend and now lives at home. They are inseparable every day, doing nothing but relying on their parents, every day.

Yes, as a sister, you can talk about him, but then again, if you talk about him, your excuse is that your parents are the economic pillars of a family, and your parents didn't say anything, then you have to know what your parents think first, so it's mainly your parents who have the final say. If you give him any pressure, unless it is a big setback or an instant epiphany, wait slowly! Really can't. Give it to a soldier for reform.