looks like you are on the right path for finding some help but I wanted to gently suggest documenting the father's behavior. I KNOW you have a ton on your plate right now. I do. I have two former NICU grads so I know the stress and heartbreak being a single parent to a baby in the nicu. It was the most awful time in my life having my youngest in the nicu and being single and having two older kids at home to deal with. BUT please take 2 minutes per day to scribble down his actions maybe while you are feeding your son or snuggling him to sleep. Keeping a log of the behavior will only help you in court. I have a log of every day for the past 10 years regarding my oldest daughter's father since he skipped out on us and was erratic in visits. It takes some time to remember to do it daily but once it's routine you'll have a notebook by the phone and it will be second-nature and you will protect yourself and your son. Someone who can walk out on their child in the hospital is capable of ANYTHING.
Stay strong, you are in the right direction. Remember that the squeaky wheel gets the grease and DHS requires that you stay on top of them constantly most times. You deserve that help. Don't let them brush you off.