Any one else notice the instant Trump was inaugurated Biden immediately starts engaging with vances kids? He literally can never help himself.

Smiling. At one point hiding his smile. Remember that he is actually Bidan.

Could be that Biden the Actor knows he can soon remove the mask and step off the stage after a grueling performance.

He seemed to time a hand gesture and a softer expression just as the singing started, like he was working up the start of the song internally.

Joe knows pudding break is coming

I think Biden is so gone he forgot which side he works for.