I think that it is a great idea! 10:30 PM is only late if your schedule does not allow it, or you have to wake up early in the morning and therefore cannot get a good night's sleep. Remember that you get a high after a workout, so sleeping right away might not be possible. A lot of people exercise at night due to schedule conflicts - as long as you are exercising, it does not matter when you do it, as long as you do something. But, you both have to be OK with working out so late.
Can he do it early morning or during his lunch break?
I say try it out a couple of time, if it doesn't work for you, then talk about it with your husband.