Can you tell me what your calcium level is, along with carbonate hardness (Kh)? How long have you had the driftwood in there? Is that real wood? How did you diagnose brooklynella?
A few things I can offer you at this stage... chances of your clowns having brooklynella is highly unlikely based on what I saw in the video. They appear to be acting like normal clowns, not showing any signs of illness or difficulty in swimming, etc. I saw no signs of that whatsoever. Fish lice? Again, can you post some clear close ups of what it is you think is fish lice? I couldn't see any evidence of that in the video either.
As for your environment and tank overall... I see a grossly overstocked tank with very little in way of biological filtration.... not enough live rock, no live sand or arragonite sand substrate, etc. Is there a skimmer running on this tank?
Nitrate at 40 in a saltwater tank is getting quite high, can you list your water change schedule (how much and how often)?
You have a bit of a mess and I would like to help you clean it up and organize it so the fish have a healthy, proper environment. Something you may be mistaking for disease/illness may simply be the results of the improper environment they are living in... which can be fixed.
One warning... do not dump any meds into that tank. To do so would risk killing every animal in there.