I don't know what the problem is. I'm not sure DH knows what the problem is.
DH is very clear that he doesn't want to speak to a GP, or see a counsellor. He is convinced they would laugh in his face. A book seemed like a good solution.
Does he find you physically attractive or does he see you more as a friend?
I think he finds me attractive - I certainly still find him attractive.
Has he ever had a sex drive?
Yes, we had over a decade of great sex.
Does he have kinks that he doesn't want to share.
I'd be astonished if he did. I wouldn't say our sex life was vanilla - maybe vanillaish - but for DH romance was always important. Flowers, chocolates, scented candles, music, wine - even when sex was good, it was rarely spontaneous as DH liked "setting the scene." He's still quite romantic.
Does he watch porn?
Again, I'd be astonished if he did. We have separate bedrooms, so I can't say 100%, but I'm at least 98% sure he doesn't.
Just go for the cliché of a night away and sexy undies.
DH has an "alpha male" career and tends not to do anything if he doesn't think he can do it successfully. I'd be happy with any form of sexual contact to be honest, but I don't think DH would risk a "night away and sexy undies" if he wasn't confident that he was going to be sexually amazing.
That's why the book seemed a good idea to both of us. A gradual re-introduction to sex, with small, non-failable steps.
FWIW, I'm not aware of DH ever having "failed" in bed, but he holds himself to a high standard. Throughout our marriage we've had occasional rows over e.g. wallpapering a room, or drilling a hole in the house for a hanging basket, and it's turned out that DH didn't want to do it because he wasn't sure how to, or whether he could do it successfully, and he didn't want me to do it either, because he didn't want me to do something successfully if he couldn't. He's very alpha male that way.