In the face of such a person, you don't have to be angry, let alone contradict him. If you have a conflict with this uneducated person, you may even do something even more uneducated, and you also appear to have no quality. There is a saying that you can't afford to hide, so let's go. Out of sight, out of mind, don't confront him. If you are infringed, you also choose to endure. After all, you will cultivate him into a more uneducated one.
For example, I have a roommate who likes to smack his lips when eating, which really makes people have no appetite at all. I hate being slapped. It's really uneducated. My parents didn't teach me when I was a child. I ate with my roommate in the canteen twice and never ate with him again. I have to find an excuse to eat later or order takeout. I can't care about others directly, and it's not my turn to educate others. Then several times when he was eating in the dormitory, it was also a bang. I really couldn't stand it anymore, so I told my good roommate who was playing next to me, stop fighting, I can't stand it. This sentence is, of course, for the person who slaps, and it is ok to remind him in this euphemistic way.
It's really good for a person to have a tutor and be polite. At least let me know what you and your parents are like. Without a tutor, there is really no education at home. It is not your responsibility to treat such people with education. You can choose to avoid.