I think you need to ask him to move out to his own home ... Using the living room as if he wasn’t there would be a childish escalation and would make your behaviour unreasonable
Whereas point-blank asking a man to move out of the home he legally owns, who nobody has a right to remove him from unless he is violent to his family, is a reasonable alternative, @Starryeyes65? 
FFS talk about jumping the gun.
A taste of his own medicine in regards to lounge usage might just wake him up to his selfishness, OR convince him that the spare room is best after all.
Besides, if OP has been unable to get him to leave a living room, how do you reckon she's going to be able to make him leave an entire house? Best to start small. & see if she can make headway.
That applies whether he is being temporarily unreasonable, or if he is actually the abusive bastard you reckon he is. My gut feel is actually kinda with you on that reckoning, but until OP wants to give more info, it's a big leap ...
Until then, if she needs to be a tad unreasonable to get her point across to a man who is acting entirely unreasonably & selfishly, so be it.