If he,s 4 I would just do a bit maybe 2 times a week and see how he takes it , there are a few things you can teach him right away , like keeping his eye,s on the ball. Being balanced before hitting the ball and swinging threw . Above all though I would make sure he,s enjoying it . Just ask him and if he wants to play more he,ll let you know . I think my mum wanted me to play but I hated tennis when I was growing up .
That is the "PC" way of doing it. It is bullshit. You can't tell me pros "loved" tennis at that age. Agassi's journey of hating tennis and becoming a pro is much more a reality than someone like perhaps Federer loving tennis and becoming pro. Kids are naturally going to get burned out and realize they don't have as much of a childhood as others, so those that become pros are the ones that realize they are playing a privileged sport so they learn to respect what they are doing, just bite their tongue or one day find true enjoyment of playing. Tennis is a very demanding sport early on and requires a constant push.