Hello Meredith,
First of all, I am sorry to hear that your husband is having to go through this. Fortunately, the ANA board provides a lot of support and should be able to help with taking some of the stress away. Since you have met with the neurosurgeon by now, I'm sure you and your husband are aware of your options, but I'll tell you how mine went.
I was diagnosed with an AN when I was 18(not in the 30's.. but still young enough for a comparison), and mine was also 5mm.I was presented with the typical three choices: A. Wait and watch; B. Surgery; or C. Radiation. Every single Doctor I spoke to(and I spoke to many!) all recommended surgery because of my age. All of the Doctors said that there still wasn't enough info for the long term results and consequences of me getting radiation (i.e. if it could cause cancer later...) I took their advice and decided to have surgery. I went with the House Clinic because they are so well known and if I was to have this surgery once, I wanted to make sure it was done right. I went with Dr. Friedman and Dr. Schwartz (Dr. Friedman is taking a job at USC, so he will no longer be there...) The surgery they would choose for your husband will depend on the problems that have occurred from the AN. Because mine was only 5mm, I didn't have any hearing damage yet so we went with the middle fossa approach. They did a "question mark" like incision into my head and my surgery lasted about 5 hours. I spent the night in ICU and then was moved to my own room, where I stayed for... I believe three more nights? I then moved to Seton Hall (a hotel connected to the hospital for patients/families) and stayed there for two nights before I could be cleared to fly back home (I live in Arkansas).
Overall, the surgery and post surgery was not terrible. I was taking tylenol after the second day and it completely controlled my pain. Since your husband is younger, he should definitely be able to bounce back. He will be very dizzy after surgery and have to learn how to walk again, but your body is able to adapt and pursue through anything and this all comes back within a few days to weeks. Anyway, I do not know if I answered or gave you what you were looking for. I do know that it is hard to find people who are younger and diagnosed with AN's, so by all means, if you have any more questions feel free to ask. I had my surgery just over a year ago so all of it is still very fresh in my mind.
Afton