Are you saying that he sleeps from the time he comes home through to the next morning? Or that he sleeps a few hours then avoids the family until bedtime, refusing to interact in any way?
The first could be a medical condition (yes, depression is very possible) or perhaps prescription pill abuse.
The second could be a statement. A passive-aggressive statement. It could be the acting out of alcoholic resentment.
You have 19 years and 4 kids and an alcoholic husband who has made attempts to get sober, and I suggest you do hang in there, and I think for you an individual appointment with a counselor specializing in families of addiction would be very helpful. You mention the insurance problem, but if you have funds for 4-6 appointments it will be very helpful to you. I think a professional opinion is worth 19 years and 4 kids.
Then take it from there.