Phal Orchid help needed

I've just been given, by my daughter, a Phal that's in trouble.
Her ex gave it to her a week before Mother's Day.
By MD, all the blooms and buds had fallen off. I suspect very poor lighting.
What I'm questioning is the white mould(?) that seems to cover the exposed roots.
Plenty of good roots in the pot, but I won't repot it until I know what to do about, if anything.
2 views of the mould(?)
2 views of the roots








What thinks you's all?

Fof