Inherited Orchid with Issue

[Shadeflower]

If you want to be sure you need to repot it and give it some fresh media while you are at it. I'd remove the leaf as soon as it can be detached from the plant, it should be ok to leave it but if it is mushy I wouldn't want to leave it longer than necessary

always soak the roots thoroughly first to soften them, massage all around the pot to detach the roots from the outside then gently lift out the plant, remove old bark and fill in with new, just inspect the roots and put it all back after cutting away dead roots. The aim is to not break any roots