Should this be seperated and replanted?
 

This orchid has not been doing great. Has a long branch that just stopped growing. I placed it in strong light and this made a few off shoots grow They seem to have separate roots and not sure it I should cut it off and plant it? Or just leave it. The main stem seems to be withering.

Not yet. Wait until the roots get to be about twice the length that it is now.

Old pseudobulbs eventually die off. When the leaves are gone and the pseudobulb withers it can be cut back. Your plant should produce new growth from near the base, but yours has also produced a keiki, the new growth you see from the middle of the pseudobulb. This is normal. When the keiki has roots at least an inch long it can be carefully removed and potted up on its own. Usually it is better to leave it on the parent plant longer if possible, but if the pseudobulb is withering and the plant isn't in great shape it might be time now.

Aside from the old pseudobulb withering, it looks like your plant might be dehydrated in general. If you are sure it is getting enough water you might want to check if the roots are healthy. It may need to be repotted.

I would seperate the keikies (baby plants) from the stem if they have roots long enough to support themselves (1 1/2 to 2 in) and plant the in the same pot with the parent. It will make a nice display when they bloom. The canes of the older part should be left (you can stake them up if sprawling out) until they turn brown as they store energy for the rest of the plant as long as they are green. Repotting with new medium can give the whole plant a boost:)

Thanks John D, PaphMadMan and King. What is the ideal soil for this plant? I water it weekly - and also mist it every other day. Should I re-pot in soil that is better at retaining water? Right now I use bark and charcoal.