Makes perfect sense.
What other people think of you is none of your business. Everyone has their version of reality. We cannot spend time trying to make others invest in and validate ours, or we risk neglecting ourselves and our responsibilities.
He dealt with the news by drinking and screwing himself over 10 ways from Sunday. It was his choice to deal with it that way. His sister sounds co-dependent and controlling...and frankly like she doesn't want to be responsible for him after you've gone.
This is not worth investing a whit more energy or time in.