[Probably not the best approach, no. He would definitely make sad faces. But he'd also make sad faces if he learned you hid it from him, mister.]
Hey... [He notes the self-deprecation here (because he's the king of it and can see it in others, welp. He reaches out and touches his arm, gently.] Keith, if something's bothering you, I'm glad you'd ask me rather than keep it to yourself. It's not bad timing. It's okay.