In English "he doesn't count" would usually mean something similar to "he isn't relevant to this discussion." For example: "No one likes my poetry. My mom does, but she doesn't count because she's my mom." The implication is that a person or thing might technically be part of a certain group, but they wouldn't be counted (if one were counting the members of said group) because they're not relevant.
That idiom is more difficult to explain than I thought. Anyway, I really just wanted to ask: is the word "contar" used this way in Portuguese?