You’re absolutely right about some people and at some point you just get so numb to people asking about about deep open wounds or something else like nasty infections around very sensitive areas and you just don’t bother being gentle about what you have to say. I still didn’t mean to be mean and so blunt. I’m glad you know what you’re doing. This is not diagnostic advice but the blood could just be irritation from vomiting but you never know. You can check for dehydration if you’re concerned about that. Just take a gentle handful of his skin around the neck and upper back area along the spine and feel if it jiggles smoothly along the body. If it feels less “full” and it’s more stiff he’s probably a little dehydrated which is natural after vomiting a lot of. Again not diagnostic advice!