Child of a Hoarder

I'm going to start this post by stating that I don't intend to sound unsympathetic, harsh, or overly critical. Trust me, I get those comments from my mother when I attempt to discuss her problems. Among many other issues, both physical and psychological, she has a shopping/gambling addiction. When I say shopping/gambling, I mean that the only way she receives satisfaction (in buying things) when she shops online are on websites like eBay when you have to bid. She loves being the "first" or the "winner" of the item. This shopping/gambling addiction began about ten years ago, and she has since gone into bankruptcy. Excessive spending on unnecessary items remains an issue in our family, but another rising concern is that all the things she has bought have invaded our home. Her interests are in antiques, things that generally look "old", decorations, that sort of stuff. She calls it a collection, but it did take her into bankruptcy, which implies that the collection has gone out of control. She has an extremely difficult time in getting rid of stuff, because she believes they might be "valuable" and that she can sell these things for more than the price she bought them at. One excuse she makes for shopping is that these items have "value" and could be sold off for a lot of money "one day". In this accumulation of items, whole rooms cannot be accessed. Beds cannot be slept in. Bathtubs cannot be used to bathe in. The stove can't be used to cook on. The table often can't be used for eating. Couches can't be used to sit in. Everything has become a decoration to display more decorations. Fire hazards are certainly posed by this amassed collection. Of course, she doesn't view it as 'hoarding' as one can argue they are beautiful things and not literal trash as is so often the perception or view of hoarders. On the off-hand, she does have a hard time getting rid of papers and documents. She locks rooms of the house so that her ex-husband or other family members cannot see how much stuff she has hidden in her room. I am ashamed to invite people over. 

I have grown increasingly more claustrophobic in my own house. Fire hazards are posed. I know that if there were a fire in my house, it would be insanely difficult, even impossible, to get out. Almost all the windows are blocked by a pile of stuff. I know she wants to move out of the house and into a smaller place in the next couple of years, but if she wants to actually sell everything, she needs to get a move on it, fast. I also know that my mother has physical problems, and if she dies, it will fall to me and my brother to find a way to sort everything and get rid of it all as quickly as possible. 

I honestly don't know what to do. Every time I address this to her, she states that I am showing disrespect to her, that it's her house, and that when I have my own home, I can do whatever I want with mine (so I should leave her house alone). It's not necessarily me I'm concerned about. My adult brother has Down Syndrome, and the irony is that my mom can't bring herself to leave him alone at home for an extended period of time because "what if there's a fire?" but then our house is undeniably full of fire hazards. I am an able-bodied, fully competent individual and even I'm not sure I could get out of the house if there was a fire. 

How can I approach my mother about this in a way that doesn't make her backlash? On the other hand, how can I just let it go, and come to terms with knowing she will never make that desperately needed change?

It is harder than many of you might imagine, living with a hoarder parent who won't listen to anything you have to say about it, who doesn't appear to care about how much it affects her kids. I would really appreciate some advice from fellow children of hoarders. Thanks.