I think Sis was in the hospital yesterday. She's in London. Video and posts on Castle's instagram. Video of her son in the hospital playing on a mouth blowing noise making thing which I cannot remember what they are called.
Sis appears to have been in there yesterday and is missing her son's graduation today as she is still in there.
It's possibly serious, missing your child's graduation is a huge thing to do and not something you would take likely.
I hope everything goes well, I don't like any of them for obvious reasons, but I would not wish ill health on anyone, especially someone with children.