Although I understand the in-laws' concern, it is your house - your marriage. It sounds as if they will be having their time with Mike so all will be fine.
I have an understanding with my children that if anything happens to me they must shield the Princess from her sister. Meddling is...
OK, one step at a time. No seizures is a good thing. Hopefully with therapy and time everything will resolve favorably. We are pulling for Mike and you. Just having him home will be a good thing for both of you.
Those of us who have found the same sort of love that you have understand your fear. Cover all of the 'what if's' and then prepare for the best outcome.