Cattleya Walkeriana needs some TLC

[BellaOrquidea]

I recently purchased some orchids online and added this Cattleya (Cattleya walkeriana v. Tipo) into the cart with the description As is: Needs reppotting. My first thought was yeah sure I can do it but needless to say that once my order arrived the plant received was not what I had expected and I am in need of advice as to how to save this Cattleya.
First of, the Cattleya came in a slotted pot which was inside another 4” solid pot. The roots had overgrown and poked through the draining holes in the second pot. The roots were brown and dried so when I pulled the smaller pot it came out very effortlessly. Once I inspected the Cattleya more closely I found that 4 pbulbs were rotten and two more have a very dark brown almost black coloring. They are firm to the touch. Additionally this Cattleya has three more good pbulbs, although one is dangling as it seems to have been damaged awhile ago. I will include some pictures so you can see and hopefully we can save this plant.