崩す is a transitive verb so it should have a doer(omitted or not)
In this sentence, the doer seems to be 彼, he destroyed himself with alcohol:
酒で彼は身を崩した。 Drink brought about his downfall.
But in the following sentence, it doesn't work well to say that 彼 is the doer since it seems that he is not voluntarily ill:
彼は少し体調を崩して, 今週は学校を休んでいる. He has been off school with a slight illness this week.
Is the doer omitted in this sentence? If yes, is a sentence like 彼は風邪が体調を崩す correct to say that he is ill because of a cold?
I don't find any occurrence on google search so I think it is not natural but I don't know why in this case?