Dear Prudence: I'm a grandfather with a 4-year-old grandson who is smart and engaging, but who frequently throws tantrums when frustrated.

My son's mother-in-law cares for him during the day while my son and his wife are at work. Several times a month I pick him up from her house so he and I can spend time together.

Usually I feed him lunch, but the other day he refused to eat. When I took him back to his grandmother's house, he immediately announced he was hungry. She said it wasn't snack time for another hour and he should have eaten at my house. He launched into a fit, which escalated into a shouting match between the two of them. She put him in time out then made him drink sips of vinegar until he stopped screaming, which I believe is a method she used with her own numerous offspring when they were young.

When I went to say goodbye he was huddled in a corner, mouth reddened from vinegar, shuddering and whimpering "I want to go home." I am deeply disturbed by the whole incident, and feel I should have done something, but I don't know what. I also don't how to raise the incident with my son or daughter-in-law.

Unfortunately, I have a feeling they will say the grandmother handled the incident appropriately. Please weigh in.

Prudence says: I wish you'd picked up your grandson and taken him with you. That would have given you the opening to later explain there was no way you were going to leave a little boy with a sore mouth sobbing in the corner when all he needed was a turkey sandwich and some understanding.

I'm betting Grandma's day care comes cheap, but the cost of leaving this boy with this woman is too high. When an adult is engaged in a screaming match with a hungry child, the adult is the one who needs to learn self-control. When she goes on to physically abuse her grandson, she should no longer be his caretaker.

But you're right, if Grandma did it to her own daughter, then your daughter-in-law is likely to say she turned out fine and her son deserves the same the punishment. This has to be handled very delicately.

Talk to your son and daughter-in-law, tell them how great your grandson is, but that like many 4-year-olds he is prone to meltdowns. Say you all need ways to handle him with sensitivity so he will learn to regulate his own behavior.

Then explain the scene you witnessed at the grandmother's house and how distressing it was to see vinegar poured down the throat of a hungry, frustrated child.

Take a look at some of these books about tantrums, and if it feels right, give one or two to your son and daughter-in-law: "The Everything Parent's Guide to Tantrums," "The Highly Sensitive Child" and this list of children's books.

If they won't take action, increase the amount of time you spend with your grandson, keep your eye on the situation, and intervene when it goes off the rails. Fortunately, next year your grandson will be in school during the day, reducing the amount of time he spends with his vinegar-hearted grandmother.

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