Mystery Caterpillar

My brother Logan found a caterpillar. We think it will be forming a chrysalis or a cocoon soon. Mom thinks  it is a green fruit worm that will turn into a moth. It eats grapes according to mom's research, but we are feeding it the leaf we found it on. Mom sprayed the leaf with water so it would have something to drink.  We found it on a fallen weed leaf on the concrete next to the house, in our backyard. This is day one!