Glad you joined us. Yes, as everyone has said, there is hope. There is also no crystal ball, unfortunately. I would suspect that a high percentage of people who are admitted to a hospital with injuries directly related to drinking will swear off drinking forever. Just like someone who has serious withdrawal or even hang overs.
However, it's impossible to say who means it and will carry on with getting the support they need (as dandylion mentioned, rehab for a dual diagnosis would be helpful) and those that simply feel better once discharged and carry on drinking.
He may have been using alcohol to medicate his depression, it's a common theme, it's also a terrible drug to use for depression!
So it's a wait and see thing really. Hopefully he is open to your input and will try rehab.