I am going to go against what most here will say and offer what I wish I had done.

GO DO IT! Seriously, bring as many family/close friends as possible and do it. Tell them the stuff will get donated, tell them whatever you need to so they don't get all freaked out. Granted they will get freaked out some. Tell them the state CAN come in and throw them out for living in an unsafe environment. Heck, call the state, maybe you can get someone to talk to them.

Ever since I was little there has always been things piled up. When your parents have never slept in their master bedroom...you know there's a problem. It's gotten worse over the years. My sister and I have moved out and the once semi-empty spaces have been filled in with junk. Every room of our parent's 2600 square foot home is full. Where do I start? My sister and I have addressed the issue with our parents and they understand it's a problem. They don't keep trash, they collect junk. It's mostly clothes, shoes, kitchen ware, electronics, and anything else you can find at your local thrift store; which is where they buy most of it. We've told them to lay off on purchasing so much stuff THEY DON'T NEED. Most of the time when I call them, they are shopping. It's not only a waste of money; they have no place to put it. I am engaged and have been with my fiancé for 4 years. My sister has been with her boyfriend for 3 years. Neither of them has been over to our parent's house. Not for birthdays, Thanksgiving, or Christmas. We exchanged presents in the car one year. I have since informed my fiancé on the severity of situation. It's time to take action before things get any worse. I'm afraid of something happening to them in the house and how someone would be able to help them or get to them in case of an emergency. I know they think it's embarrassing, but I love them no matter what and just want the best for them. And for our family to have a better close-knit relationship we've always wanted.