Hi Ellen - sounds like your husband is doing very well! Good for you both - it's hard work making it through this treatment!
As far as return to work goes - it's not an unreasonable goal to be back at work in 5 months. I was fortunate enough to go back to work on a part time basis 6 weeks after treatment - I pushed it a bit because I was going totally stir crazy at home and getting back to work made me feel like I was getting my life back. Keep your mind open though - there were days shortly after treatment that I thought "I could really be working" and other days that I thought about needing to extend my FMLA for another 3 months - it's a bit of a roller-coaster ride with ok days and not so good days - you can just never tell how those days are going to stack up!

You mentioned that he wants to get back to his therapy practice - I know that it was hard for me to talk too much in the first couple months after treatment so he may run into that as an issue - talking a lot was fatiguing, a bit painful and as those 2 problems increased during the day I felt like the clarity of my speech was reduced - frustrating!

Good luck with these last treatments - it's a big deal when you're down to single digits!!