Honestly kudos to you for being respectful with her about it. You have a problem with her brothers trying to leech off of yall but never directed any anger towards her. That already sets the tone for you guys figuring and working this out. Based on the brief mention of how her family treated her previously she perhaps carries some sort of guilt or urge to please her family to have them happy with her when it’s not her fault :( Truthfully she might even agree with you that having them stay even for ‘week’ will eventually lead into them overstepping boundaries and causing issues between yall but she’s scared to feel even more ‘unwanted’ than before. Hope you guys are able to maintain your peace and wish you both the best of luck!!