My friend's elementary school kid hasn't had any vaccines since birth. Her mom is against it. Should I worry about this kid playing with my 10 month old who has been vaccinated (as far as 10 month old can be...) ?

My baby hasn't had all the vaccines yet since they come in stages. I just worry about the vaccines my baby has yet to get meanwhile coming into contact with a known non-vaccinated 4th grader. How can I tell my friend that her kid needs to stay away)