Nallabelle

The good news is that he recognizes it. There is a fine line between addiction and dependency. I am not an expert or a doctor- only an addict. I can share my opinions on your situation.
Generally "addicts" are more obsessed with their drug of choice (often referred to as DOC) than someone whos body has simply become dependent on it. Addicts abuse their DOC. They tend to count pills and revolve their day around their next dose. Most addicts start out as people dependent on the meds for pain, and it escalates.
I have never taken dilaudid. I am in recovery for an addiction to vicodin, which started after giving birth to my second daughter. I needed the pain meds for a couple weeks legitimately but loved the feeling and energy it gave me so much, I could not stop. Coming to this site, going to NA has taught me sooo much about addiction. Its way more involved than I could have imagined. Never thought this would have happened to me- there are a lot of misconceptions about addictions- it can happen to anyone.
As I said Ive never taken your husbands DOC. I would assume that a good doctor would help him taper down before quitting. Generally speaking, detox off pain meds will not kill you. I dont believe their have been any deaths reported from it. However, you will feel like crap for a while. The WORST of it is over in 3-5 days after quitting. During that time he will experience flu-like symptoms, anxiety, depression, lack of sleep, diarrhea, fatigue, etc. It is important to come on this site during that time. There is a lot that can help him while detoxing (OTC meds, etc).
The main thing I think you can do right now is be supportive and encouraging. It would really benefit him to taper off to lower his tolerance before going cold turkey. After the first 7-14 days, the physical symptoms will subside (potentially not the insomnia) and the mental will continue. This is often the most difficult. It will also more clearly define if he is addicted or dependent. If he is going crazy craving it and obsessing about it, he is likely addicted at that point. If this happens, you need to be able to recognize it and deal with it appropriately. If he has never abused drugs or alcohol in the past, then I recommend being understanding him and nipping it in the bud. You have to be patient.
Gather as much info as you can. He can do this, but it wont be easy. The more educated you both are the better it will be. The most important things are for him to be honest (and FEEL LIKE HE CAN BE HONEST) with you and for you to come here during detox so we can guide you.
Good luck!!