So very very sorry to hear this. Dave was such a nice guy to work for and with, and always ready to help out or answer a question. He was the Gold standard.
I’m so sorry to hear this. All I can do is offer you, your mom, your brother and the entire family my condolences. Dave was the kind of person that it didn’t matter how long it had been since the last time we saw each other- it would be as if we were still working together.