Speaking to my hoarder mom's therapist. Any advice?

I posted a while back about an ultimatum my dad set for my mom to clean out the house. Turns out he had a very reasonable tipping point. There's so much stuff in their bedroom. It's piled on their bed during the day then at night, the have to pile it around the bed, then in the morning they basically have to "dig" their way out and put everything back on the bed in order to leave. My dad woke up in the middle of the night and really had to go to the bathroom and nearly didn't make it in time. He said he tried to wake her to help but she sleeps like the dead. He was throwing stuff on top of her in order to get out and she had no idea. I think that made him scared and was the final straw. He was too embarrassed to tell us this initially but he is so checked out now. He's now sleeping on the couch until "everything is gone".

I've convinced my mom that I should talk with her and her therapist to figure out how to handle this. From recommendations on this sub, I've realized she's likely lying to her therapist so I went in and took pictures. It's so much worse than the last time I was at their house.

Any recommendations on information I should get from my dad/things I should think about bringing up with the therapist? I honestly didn't expect her to agree but I'm thinking my Dad's confession managed to make her see that there is a bigger problem than she's ever admitted before