Does this constitute as section 8 fraud?

I know someone who is going to a community college in the fall. He is 21. His dad is a veteran who is 74 who works hard, but sadly couldnt keep up with his mortgage and is losing his house to foreclosure from financial issues and declared bankruptcy. He will be homeless if he doesnt find a section 8 apartment soon. The only one avaliable is a 2 bedroom apartment for veteran homeless families with low income. That means the only way the person's father can get it is he needs to find someone to co sign for the lease that has low income as well. He asks his son to cosign and live with him in the apartment. They both qualify for section 8 due to low income. The son was living rent free with another relative before his father lost his house and needed someone to co sign with him. If his son co signs on the lease so his dad can have a home in the apartment, does he have to actually "live" in the apartment or can he mostly continue to stay at the original place where he's at sometimes because its closer to school? I'm not sure if it might be illegal or fraud but this is the only way the son can help his father can get a place who really needs it

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