The Falklands veteran, 62, had to put an end to his roadside protest, outside the Newport headquarters of Combat Stress, on Sunday morning.
While he recovered at a nearby hotel, his supporters, who have travelled to Newport from around the country, took his place and vowed to fight on in his name.
Gus, who is now eating a small amount of rice milk and baby food, said: "My core body temperature plummeted overnight, my pulse shot up and I could not get warm. I am in bed now, because I had to call it off.
"The next two days would probably have killed me with the cold.
"When your temperature plummets like that and your pulse rate shoots up it means your body is under real stress.
"Other people are now taking the chair."
Gus is set to meet Combat Stress CEO Sue Freeth on Tuesday and is hopeful there may be some resolution to his situation.
"They said they would come and give me answers to my five points. It has taken 21 days to get there and if it is just more rubbish on Tuesday I do not know what I will do."
On Friday morning Gus was rushed to hospital after concerned supporters noticed he was feeling unwell. But he was back at his spot over the weekend however his condition worsened and he was forced to quit.
Mr Hales initially stood down from his two-week protest on Remembrance Sunday, but despite an apology from Combat Stress for the way he was discharged, and a pledge to review other cases of veterans who had suffered from the same treatment, he said he would continue his campaign until he had a concrete promise of government action.