Functional alcoholic going cold turkey! Is it possible?

My husband has been functional alcoholic for past 8 years nearly. He used to 350 days of the year hard spirit. I told him to stop, otherwise I am leaving. So he decided to stop because of warning.

Today is his 3rd day without alcohol. But past 3 days he is been eating a lot, his appetite has gone really up. He is doing treadmill and just focusing on eating. Behaving normal so far.

Just want to know is this normal? Or do I have to be ready for any other symptoms. Also will he be able to quit like this without any additional support?