What a star you are beckyb, you are almost observing from a third person perspective that's the detachment you'll have seen many talk about.
Your H's "project" does seem to be very high maintenance doesn't she (this comment is not wishing her ill)? As a mr nice guy he'll be loving all the opportunities to fix things, he can be a hero. As there is so much for him to do, he'll soon burn out if she doesn't continually give him praise and tell him how wonderful he is, which depending on how she feels, may or may not be happening - mr nice guys give love and attention with the unspoken, but expected condition that they are rewarded with similar.
Glad your time with your BIL and his wife went well.
- Nobody has ever learnt anything important from happiness and success; problems make us grow - Consult your plan, not your feelings - If you haven't set goals, how can you expect to achieve anything?