If someone doesn't want to answer your question, and uses mute withdrawal to get away from answering the question, or just answers with a vague response, just leave them the hell alone. I hate it when people probe me for information that's absolutely none of their goddamn business. It's up to me to share things, not them.
And to add to things... if someone doesn't go out partying till they puke doesn't mean that there's something wrong with them. Some people are more into hanging out at home. Just let an introvert be an introvert, for Christ's sake!
“Thoughts are the shadows of our feelings -- always darker, emptier and simpler.”
― Friedrich Nietzsche