It appears he hasn’t submitted yet, so nothing is going to be flagged to the college.
It’s not so much he is hurting his chances by applying RD, but rather, that he improves his chances by applying ED.
I’d apply ED. As others have mentioned, if he can’t afford it, he can’t afford it. But he should also understand that some need aware colleges might reject him simply because he is applying for FA. This is more likely for students on the border between being accepted or denied. Need aware colleges are more likely to admit the students they REALLY want.