Child tax credit question

Hi all, I hope someone can help me here. There is a long back story to this question, but the essentials of it are this:

My brother-in-law is due to move in with myself and my husband, he is in full-time education and we have used the child tax credit calculator which says we are entitled to some benefits. However, my father-in-law is insisting on continuing to claim the child tax credits for this child on the same claim as he makes for his other children, even though he will be living with us, permanently.

FIL says he will pay us the money, and technically we could get more money by doing it that route, but as far as I am aware ctc can't be claimed for a child that doesn't live with you (unlike child benefit, which can be as long as the money then goes to whoever is caring for the child). Am I wrong in this? I can't find any clear information online and would like to be able to say to FIL that what he is asking of us could be fraud and that we will make the ctc claim ourselves.

Thanks for reading!