Hi Sophie's mom,
My mom used to come to visit me to the US twice a year. She would stay around 3 months each time. My US friends could not understand why i allow my mom staying so long. She was used to giving pretty negative feed-back. There was a reason for her to be in that way, but anyway, sometimes it was hard to deal with her. I come from a place where parents are very much regarded; so there are cultural issues involved. I am giving all this background so you understand where I am coming from when telling my experience.
The last 2 visits my mom had I had a conversation with her. I told her I needed her. That it was good for her to come to visit and stay with me. And I told her that her negative feedback was bad to me, and that I needed her support, telling specifically what she needed to do in order to help me. I told her that it was good for me if she come, but I gave her tasks to do and "don't s". I was afraid of doing that, but it did work. My mom was very happy to help me. I found concrete things for her to do for me, and also I could see how she did her best not do the stuff I asked her not to do. To mom, it would have been very hard if I had told her I did not enjoy her visit. Instead, I told her I needed her visit but i told her I needed her to do certain things. You may remember she passed away last year. I am very happy I could work out things with her. I missed her a lot. Of course, when I was in the US it is true that I did need to see her, as I was so far away from home. OK, hope this is useful.