> Finally, something that people might not think about: If he misses something someone said and asks you what it was, never say "it's nothing" or "it wasn't important" or "it was just a joke" no matter how minor the comment was. Just repeat it no matter what.

This is absolutely critical. It's hard enough to interrupt multiple times (especially when you need to ask about the same misheard thing multiple times) and being shut down makes it even harder.