Help with my sisters Blc.My Orange 'nn'

I need help brining my sisters orchid back to health. It is a BLC. My Orange "nn" It was doing fine in the spring even putting out a new shoot. But after about 3 inches of growth the shoot turned black and mushy and died. A few months later the leaves on the largest spike turned yellow and fell off leaving the cane to go brittle.
She had it in a SE window about 3 Feet or so away about 2 feet lower than the sill on a small table. It got good light here though it was coming though sheers.
She fertilized it every week with a watered down 1/2 rate orchid fertilizer by soaking the pot in a bowl for 10 mins.
Home temp is about 75-79 degrees F with some but not much nighttime fluctuation. I know they like this for flowers but We are just trying to bring it back to health for now.
Any help on care tips would be great.
to might light ?
to much or little water?
Should we repot it since its had time to adjust and its clearly not in a greenhouse so maybe drying fast? She would pull back on watering when she felt the medium was still damp. It is large chunk bark.
Should we stop fertilizing?
So many factors but it anyone has had expirence with this type of orchid and may have insight that would be great. I can also provide more info if needed.