Hello
While I am not a doctor I do work in a children's hospital as a therapist....
I think what you may have seen is two isolated events.  We have had a lot of
Gastrointestinal illness the last couple weeks that presents like your second
experiance.  You may want to have him tested for Rohto virus...keep him
hydrated if you can.. that is what brings most of these kids to the hospital
is dehydration.
Good Luck.. hope he feels better