Help our Rooster "Braveheart" seems to be very sick

It's been about a week we noticed that he went through a molt and is still growing the feathers back, but he stopped crowing and started to stay away from the flock and started to act drunk and now he's lethargic. He can't stand up and he's very wobbly.

I quarantined him and brought him inside the house 2 days ago and feeding him vitamin water every other hour alternating with a mash of cooked egg yolk, honey, beef cat food, oatmeal, pinch of vitamin powder, and yogurt. He did well with the vitamin powder and honey at first, but doesn't seem to be getting any better.

He's about 3.5 years old, only rooster with 14 hens, The hens are molting and have stopped laying. He was dewormed with invectrum a week ago. What should I do now? Any advice would greatly be appreciated.

Thanks!

 

Thanks, I will get some safeguard. The flock is also dewormed with Wazine 17 in their water, I switch between the two every 6 months. The rooster is not standing up because he is too weak. No poop the first day, but after the vitamin water his poop had a green smelly substance and was watery which I figured was the water. He drinks about 8 oz a day with a few tablespoons of the mash. He has lost weight due to his illness and not eating or drinking before I brought him inside. I'm not sure what else to do, I wish I knew what is was and if it's contagious.