Phobias will be phobias. 🙄
@Chocrabbit Therapy will help your DH, and how good that he's seeking it out now. He seems like he actively wants to make a good partner for you for birth, so don't discount him just yet.
My husband is the same. He's extremely needlephobic, and just the thought of them can send him all woozy. He's also not fantastic with the sight of blood. Being jabbed himself (he needs regular bloods taken) he needs to be laying down.
But when it came to the reality of me getting jabbed he was fine. He made sure he kept his fluid and sugar intake up, tried to not build it up on his head, and either left the room or looked away when I was having a cannula inserted or any other injections. He was instructed that if he felt faint at any point to not stand up, and to slide down off the chair to sit on the floor. The midwife will call for aid for him. He wouldn't be the first husband we see faint (I work in the obstetric theatres) and he certainly wouldn't be the last.
That being said, I did choose to bring along my Mum for my first labour just in case. But she wasn't needed. Neither was DH to be fair, but I'm glad he was there.
With our second it was just us two, and he did superbly. He gave me all the support I wanted, then made it through an epidural and a C-section without wavering. He opted not to look when the drapes were dropped, as he had built that part up in his head, but that was it.
Some men just get overwhelmed and overstressed by the whole thing, but with some education and preparation about what can happen and what to do in those events will help give him focus and reduce stress when the real thing happens. Give him a chance. He'll probably surprise you.