A narcissist will use the phrase 'get over it' because, to them, your concerns are trivial and if it's not about them, then they're not interested. This is extremely accurate and fit two men who have been in my life. No dealing with either of them anymore
I use to feel bad but not anymore. Took a long time to realize some people don't deserve my time or emotions. For my inlaws. Shame on your narcissism. Learn to behave like an adult. Terribly sad how you all treat him.