It's really easy to be angry at May for this. She neglects the entire family the same way their parents neglected them.
But she had to establish her own boundaries to keep herself safe, and this was in part a result and cost of that. Maybe it was also a matter of a gut feeling or an instinct that told her, "things are gonna be bad, so bounce for awhile actually." But how long you're supposed to bounce, or how hard you bounce period, is something you have to decide, and it's easy to make mistakes there.
She is going to heartily wish she was more connected to them and could have prevented this from happening...but only once this is resolved hundreds of years from the time of this story. Secrets have a pretty high price point.