giving a 4 month old sugar

Cynthia
We were at my parents for my moms birthday and my father decides to give our 4 month old son some cake frosting and ice cream. Yea it was a taste but it was like 4 tastes of each!!!!! I had my back turned helping my sister dishing out cake and he had already done it!! My husband is very upset too!! First if all he is far too young second of all we want to be the ones giving him tastes of new foods when he is old enough. I told my dad to stop and he gave him another bite. He says how he gave it to me and my siblings and we are fine like I don't care this is MY baby and I want nothing but the best for him. He disrespect me and my husband I don't even want my parents babysitting anymore ugh. Yes I'm a FTM but I don't care babies do NOT need unneccary sugars!! He also gives my 8 month old niece tatses of coffee on a spoon he thinks this stuff is funny like our children are not dolls or expiernments!! Anyone else have parents that do this kind of stuff????