My mother wants to visit for two months, living in her motorhome. My husband wants only 1 month. Unreasonable?

My husband and mother do not get along. Long standing battle as he does not want to be told what to do or to be put down by her. She does do this. My mother owns property adjacent to us and wants to visit us for a two months, living not in our house but in her motorhome so she can spend time with her grandchildren. My husband only wants her in the vicinity for one month. I have informed her and now my mother is upset and does not want to come at all. Says she feels unwelcome. I am in the middle and do think my husband is being unreasonable. He says if she comes for longer her will move into a motel while she is here. Thoughts??