What can I do to make her get rid of all this junk?

Ok so my house is ok. The only problem is that my grandma is literally a hoarder. She keeps our back room filled with junk. The whole house is a pig stein. She doesn't understand that this is not healthy. We have had mice problems and now to make it worse we have a roach infestation in our kitchen. The last place you want to see them at. I need a way to make her get rid of all this junk. The way we live is not ok. Can I do anything? She has custody of my younger brother and these are not ok living conditions for him. Thank you