Sounds like they were doing good and something major happened in their life. It is a shame neighbors don't stand up for each other anymore and help when the other is struggling. I do miss the old times.
I would like to add this. If you think she needs more time with her horse, you could help her by doing things you do know how to do. Things like mucking stalls, brushing out the horses, helping with feeding, or maybe there are other chores that could be done to free up her time to do other things.
To put it bluntly you have to step back this is not your horse. You can have your feelings and tell her about them or you can step off and remind yourself it is her horse. She can handle him as she sees fit.