Fungus on rotting mount

[malteseproverb]

Does anyone have any advice on how best to remove this orchid from its mount with the least possible amount of damage?

I've had this rhyncholaelia digbyana for about 3 years. When I got it it was in bad shape. I mounted it and it did very well for a while, slowly getting bigger and bigger. Last year I noticed this scummy looking fungus growing on the bottom of the mount. I repeated treated it with physan, sometimes sprayings, sometimes soaking over night. Nothing happened except that most of the roots died. The mold spread to other parts of the mount, and I realized it was coming from within the mount.

I decided to ignore it for a bit, give it more sun (it gets TONS of sun), but then recently I noticed one of the latest growths has just turned to mush. I know it's just a matter of time now before it takes the whole plant.

I would like very much to save it, as it's very sentimental to me. I inherited it from my grandmother-in-law, and it's the national flower of Honduras, where my mother is from. Any advice would be very appreciated!