That matters for how much someone picks up, but the other variable is how much the person who is feeling bad shows it. Even people who are close to me often have trouble telling I don't feel well unless I'm *really* sick, even if they're normally good at reading that.
I had to drop out of boarding school because I was sick and the school didn't believe me. Turns out I had mono, but the nurses never tested me and thought I was faking it or depressed, because they didn't interpret my demeanor as that of someone who was sick.
Thanks, but it worked out well! Probably wouldn't have married my wife if it hadn't happened, and given how positive that has been I have trouble believing the alternatives would have been better.
Life is weird like that.