all right! there are two poeple i have in mind while answering you. you, and your grandson. Because "the mother" seems happy enough and she is not the person asking for help.
so what does a grandson need? a place to come and be appreciated, loved, accepted as he is. He needs a grandma to remember his moments of glory, to listen to his stories and tell him about his father when he was a kid and how different or similar they are. He needs a warm meal to sit and eat while she affectionately watches his every bite and a memory of a constant hugging smile.
what does a grandma need? a grandson who likes to come over, tells her about his grades and aspirations, confides in her, likes her cooking, likes her cat. she wants to get to know his friends, perhaps he will bring them over to a real cool granny, to a sane place in the world where he can relax. a granny needs a grandson to happily remember her birthdays and call her for homework assistance or whatever else your specialty may be.
we each have our turn at being kids, parents and then grandparents. we learn as we go along or we dont learn. its our own life, no one can save us our mistakes. acceptance and love is the biggest thing we can learn here. experiance that and your grandson will be a greater man.