Hello zazz!
I have a phal in the exact same condition, well, sort of, is been amost 3 weeks since the horrible finding of almost no roots.
The guys here at the board are wonderful and super savvy, one of their recommendations for my phal was to "sphag-n-bag" it putting the whole chid in a clear plastic bag (i.e ziploc) with a little damp moss (not in contact with the plant) and let it sit in a warm shady place, until nature does its thing and new roots grow.
Hope your phal recovers!!!!