Is Trump Scared Straight?

Seems to me the president has been relatively quiet and subdued on his twitter account recently. That's just an impression which may be wrong because I don't follow him.  Instead I base my impression on the tweets of his that others retweet and comment on.

Anyway, if it's true, why?

• one answer would, of course, be the prospect of impeachment which is not something an insecure person would  feel good about.
• another possible answer, although it comes too close to a conspiracy theory for my comfort, is the possibility that his recent trip to Johns Hopkins was an indicator of some sort of health problem.  As self-absorbed as he is, he's got to be super conscious of his age and the end of life.  That might chasten even him.