A questioner asks can we purchase pork, alcohol or cigarettes for non-Muslim parents? Prophet Muhammad (PBUH) said there is no obedience to a creation when that means there is disobedience to the Creator.”
Whether you are using your money or their money for whatever it is that it haram they need buying, you shouldn’t do it. So how do we deal with this situation?
You need to overcompensate to them by apologising, explaining to them and doing things for them that is OK and that makes them happy. The issue it to not make it into a big deal. As you grow in your own religion do not neglect your parents but do not do anything haram.