Comas are a natural human/animal ailment and have existed throughout history, even if the phenomenon was known by other names.

There are already some good answers about comas, their treatment and their history:

When people fell into a coma during medieval times, did they all die of dehydration after a few days? which has a range of fascinatingcontributions covering modern and historic treatments.

If you fell into a coma in the middle ages what would happen to you?, also with a range of interesting answers including a great one from u/jpallan about Henry V