You be the judge: should my brother stop hogging the living room while staying in my flat?

A writer says their younger brother, Seamus, is staying in their flat for six weeks, and tensions are rising over space and house rules. The author explains that last time Seamus lived with them—after their parents sold the house—she turned her living room into a bedroom. This time she bought a sofabed for about £400, but Seamus has reportedly changed the flat’s setup, including adjusting the shower temperature after which the author was burned, moving chopping boards, taking spare keys, and preferring an earlier bedtime. The dispute centers on whether the brother should follow the host’s routines when the room is temporary lodging. The brother argues he needs his own space and points to the arrangement benefiting the author as well, while the author says they don’t charge him money because it’s not a lodger deal.