I am not sure that there is anything worse than watching your tiny child retch for days. I always feel so helpless when my babies have a tummy bug. It is so much more physical and visceral for them than it is for adults. (((S2))) I'm happy he's feeling a bit better.
You did the right thing in offering time with S2, but it really is for the best that X declined, for all of your sake.
And as confusing as it is, it must feel nice to have a couple of thoughtful texts from X. A few messages where you didn't have to have your guard up, didn't have to pre-meditate your communication. I am sure he will be back to being an a-hole again in the near future, but for a moment, you get to feel what coparenting would feel like if you weren't coparenting with a cluster B human.
Maybe his generosity will last through the holidays?
Either way, YOU, dearest Scout, are deserving of respectful messages all the time. From everyone you interact with.