A few years ago, H was in the hospital for 2 weeks with heart problems. I never told difficult child or the 2 youngest boys because they were all away at camp. The 2 oldest (19 and 20 at the time) knew because they were home but we all agreed not to tell mother in law or their brothers. H would call his mom from the hospital but she doesn't have caller ID so she never knew. I never even told our friends.
I've had 2 relatively minor surgeries in the past couple of years and haven't even told my closest friends or my children. I've long since stopped wondering where difficult child gets his absolute refusal to disclose personal information from.