Hi there ~
I understand your concerns. I am sorry to hear about your 3 yo having some delayed milestones. The loose stools and vomiting
are concerning however, and I wonder if your baby had to be on medications to stop these episodes or to be on antibiotics for a longer period of time. I hope you take your son to a pediatrician
as soon as possible if the vomiting is worsening. I hope this helps.
Take care and have a lovely day!