Disregarding rare exceptions, most of the parents love their children and sincerely want them to succeed.
The method they adopt to help guide their children to the right path depends on their education, knowledge and past experiences. Sometimes it is just the health condition or stresses in life that shape their communication style. But, rest assure their intensions are always pure and sincere toward their children.
Now their style of communication may not be aligned with the expectation of children who are born in a different culture, environment or at least in a different generation.
Focus on the inherent message they want to communicate and as much as possible disregard the delivery method and always maintain respectful in your posture and language.
In response to their rude, denigrating and offensive style speak to them with respect and see how quickly they will melt down. If not, try talking to them one-on-one with when they are in a good mood and explain how you feel.
Still doesn’t work, then talk to one of your grandparents, uncles or aunts (his parents, brothers or sister) to communicate your message on your behalf.
Still doesn’t work, then with respect try staying away from him and communicate briefly and as necessary.