My father is keeping my child away from his dad. We've been out of the hospital for three days and…

My father is keeping my child away from his dad. We've been out of the hospital for three days and since neither one of us have a car right now my dad agreed to pick him up everyday to spend the day with us. Well that hasn't happened and I feel so bad and I don't know what to do at this point. We still have about a month before we can get our own place and I don't want him to go that long without seeing his son