I would not wake your lo to feeding during the night. This might start to cause problems and may be harder for you to get him to sleep again after waking him.
I agree if he is not taking much at the DF, you can cut out the cluster feeding and concentrate on the dreamfeed. If you see that this is helping him take more at the DF, then you can carry on without the clusterfeeding.
If he still takes a little at the DF, then you know that the DF is not the way to go, and that clusterfeeding may work better for you.
Hugs, I know how hard it can be when your lo gets sick, everything seems to go out of the window. My DS has just gotten over his cold, and now he has given it to me
argh.
Please keep us posted on how you get on.