UC housing costs - paying rent to a relative who lives at the same address

Can anybody confirm for me whether housing costs can be awarded in UC where rent is being paid to a relative who lives at the same address? CPAG handbook (p. 89) says DWP “may” treat someone in these circumstances as not liable for rent, CAB AdviserNet is more definite, saying they “won’t count as liable”. The client rents a room in his brother’s (mortgaged) flat; the rent is well within the amount of the under-35 LHA rate for the local authority area.
If CPAG is correct, how would the client go about ensuring that he isn’t treated as not liable?

I think Schedule 2(5)(1) of the 2013 regulations is going to prevent this; Universal Credit will treat the client as not being liable because the liability is to a person who lives with them, and who is a close relative (which includes brother, under Regulation 2).

If, for example, the owner-brother had a mesne tenant, who in turn sublet to the client-brother, that would (I would think) bring in Schedule 2(10) and the treatment of non-liability where it appears it has been contrived to secure entitlement. I may just not be feeling very creative this afternoon but I am struggling to imagine a set of circumstances with these brothers where they could escape the first problem and then also avoid the second - sorry!

https://www.legislation.gov.uk/uksi/2013/376/schedule/2/paragraph/5/made

Thank you - the regulation does look more cut and dried than the CPAG wording seemed to imply.