My Step Daughter Feeds Our Grandchildren A Horrible Diet. The

My step daughter feeds our grandchildren a horrible diet. The 5 year old girl has green round poop and the almost 3 yr old boy has been diagnosed with GERD that creates asthma like symptoms. They feed the 3 yr old often (like a cup of cottage cheese) at 2 or 3 a.m. when he wakes up. Am I overreacting about the harm that's being caused?