How do I convince my parents that their home is not safe or healthy to live in?

My parents' house is disgusting. There's mold on the ceilings in both bedrooms and the bathroom (there might be more), and it causes a 'musty' smell throughout the entire house. You can even smell the musty smell on my parents when they leave the house. The floor is warped, so the carpet no longer lays flat in the living room. The fridge has rust all over it. The stove is EXTREMELY dangerous in my opinion. The kitchen sink doesn't drain on one side. The toilet doesn't flush. The back screen door is rusted and falling apart. The basement is completely unfinished. The roof of both the house and garage needs to be replaced SOON. Also, the house is small, so they have so much stuff in my old bedroom that you can't even enter it. There are also huge piles of stuff sitting all over the living room. My parents are poor, so they can't afford to fix anything or to move. I've tried talking to them about it MANY times, but my dad doesn't listen, and my mom agrees with me then says she'll do something about it and never does. They don't take care of themselves either. They both have some sort of fungus on their fingernails and don't go to the doctor for it. My mom hasn't gotten a haircut in years, and her hair is almost down to her butt, so I got her a gift certificate to get a haircut for Christmas, and she still hasn't used it. That's the part I REALLY don't understand. Even when they have the money they don't take care of themselves? Are they that lazy, or is there something else going on here? This has been going on for years, and it keeps me up for hours at night worried and frustrated. My parents are the nicest people otherwise. They still have friends and both work and are able to function normally in public. They have met my boyfriend, and they get along great, but I would never take him to their house. I feel like I have a lot of issues that have grown out of this situation as well. I have a lot of pent up frustration and feelings of embarrassment not only for them but for myself. I feel like the situation reflects on me even though I'm not the one who caused it. I'd literally do anything at this point to fix this, but I feel like I have no options. Do I just grin and bear it and accept that my future husband and children will NEVER set foot in my parents' home?