Hey, brown and squishy IS a technical term around here ;-). 3 years means the medium may be breaking down.

I too hate to repot while it is in bloom, but many phals will take it in stride, or so I am told...and better not to lose the plant. Still, if you have only been watering once a week...how are the newer leaves--do they look OK??? If so, you can probably wait. You can also gently slide it out of the pot and peek at the roots and slide back...that won't really disturb things.

Mine that had wrinkly tired looking leaves last year, I did wait until after the bloom finished... mostly because newer leaves looked OK. It did have mostly rotted roots, but a couple that were OK, and it made it.