My friend is kind of gross

One of my best friends is not a clean person. I know she doesn't wash her hands after the bathroom, I've seen her do it while at a public bathroom. I don't care if she thinks she "didn't touch anything" the fact is, pee may have soaked through the paper, and  she touched the bathroom door where people who HAVE touched something have touched. Well anyway her house is disgusting. When I go over, I know to expect I'll be given a dirty glass, so I try not to drink unless I wash the glass out myself first. Her dishes are put away with chunks of food still stuck to them. Her boyfriend is an alcoholic and he pees on the wall and the toilet and the floor and yes it's left there long after its dried and yes he does it in the bathroom the guests use. Generally her house is picked up, there isn't too much stuff on the floor except clumps of animal hair, and when she does vacuum it looks nice until you get close and see that almost everything is covered in some kind of grime. Like the faucet in her kitchen has a layer of grime so thick that you can feel when you touch it and I just want to scrape it off. Basically it's a nice looking place that is covered in a layer of grossness. We have joked about her hygiene and her cleanliness together and I have offered to help her clean when she complains about cleaning, not in a judgmental way but in a let me know and I'll help way and she always says no. Anyway the issue is that she wants to host a bridal party for me, and another friend of mine offered her house too and I agreed to my other friend's house. Now the friend with the dirty house is upset because I didn't pick hers and she asked if I think her house is dirty,(she asked this because I mentioned a family members dirty home and how I couldn't do it there) I don't want to hurt her feelings but I really don't want her to host it or even bring food because I know they'll be made with dirty dishes. Is there a way to tell her yes your place is dirty without her hating me? I am sure she would clean the house if I let her host but I know it would be superficially clean rather than actually disinfected and cleaned.