Saving Grandad's Orchids

[poppy86orchids]

Dear anyone who can help!

I am completely new to Orchids. I used to sit and admire my grandad's orchids, even brought him one. He passed away suddenly in August, and I have been given a number of his orchids. I only wished I had asked him how to keep them.
The one causing me the most trouble is the Vanda Blue Magic (though its purple, not blue at all!). My mother decided to pot it, but I quickly removed it after reading that they do not tolerate their roots confined. I have put a plastic mesh pot upside down in another larger pot and I mist it daily. The leaves look very green and strong but the stem has turned brown and I've lost all flowers. A friend told me it only flowers once, discard it. But someone else told me to cut it to 3cm from the base...
I am so confused!
Can someone point me in the right direction for help! I have put it in a sunny position. ALso upon reading your very informative posts to others, I wonder if a UV light will help it.
Any help will be greatly received. I'd hate to lose my grandad's plants.