He's not even a hypocrite, as that would imply there is something in all that quacking he's doing...and there clearly isn't. Alcoholic projecting what he knows about himself on to you. Quack, quack, quack.
Don't you feel bad for one minute about your kids spending time with their doting grandparents, who sound wonderful. The relationship between a child and their grandparent is one of the most precious relationships on earth...what a GIFT you are giving your kids.
I treasure the relationship my mum has with my kids....she's another adult who will love them unconditionally - and they NEED that given the inadequacies of their alcoholic father. The more intimate relationships they have with normal, healthy, loving adults - the better. Another adult/s that they know they can trust...wonderful.
Don't doubt yourself. You and you kids are blessed to have them be so involved I. Your life and their lives.
Take care.