My thought process behind my quiet and kind response was that everybody is allowed to experience their emotions, however they need to be respectful and you cannot address somebody else in anger (especially when they are not at fault).
i think this is dead on.
there is a fine line that youre talking about. in general, our loved ones are needy people...needy for validation, needy for reassurance. do too much of either, and you creep into an unhealthy dynamic, but in the best case scenario, theres gonna be some imbalance.
it sounds, from your account, like you walk(ed) that line pretty well. grabbing coffee for a rushed partner having a bad day is sweet, and thoughtful.
i suppose that my advice would be dont try to do too much. saying things to calm and reassure him is great, its probably one of the reasons he loves you! just dont expect that you can talk him out of it, and consider the balance between supporting someone who has sleep troubles, and being able to get a good nights sleep yourself. its hard to support another person without that!
BPD anger management
in other words, dont manage his anger for him.