I can't sleep on planes either. I would probably not recommend staying up the night before of having a drink unless your husband sleeps easily. If i were to do that i would just arrive at the other end really cranky and with a headache.
The nice thing about just doing it in one leg is that at least its over with. If he does a stop over the journey will take longer and he will have 2 flights to contend with rather than just one.