Bacterial or fungal infection on Vanda?

[Sjay76]

Hi,
I’m new to the forum but have a few years experience with orchids. I’m fairly new to Vandas though and have a baby plant that seems to be doing well and this one which I’m afraid is I’m dire straits . I bought it a month ago and it seemed to be healthy, it had just finished flowering and was thus discounted. After a week it started to show yellowing/browning leaves about half way up the stem. As the browning started in the centre of the leaf and not at tips I suspected a fungal/bacterial infection so treated with the only thing available to me here that has worked for me in the past ( on phals mostly) -. Long story short after a week it seemed to be worsening so I retreated. Now a month on the stem is mostly yellow too. The roots to me appear healthy. Is there anyway to save it or the Keiki growing at the bottom?
BTW as it is early spring here in Northern Italy I still have my orchids in the bathroom at around 17-20 degrees C with quite good humidity and moderate indirect light.