Yes it is normal, children feel very left out when a new child comes along, they have been the baby then they are usurped, its tough on them, you say he gets more attention, make sure it is the right attention, he could do with Dad doing some one to one work/games with him. and you reading stories, having fun, very often the older sibling gets left out unwittingly. When he throws a tantrum sit him on a chair or seat and tell him he has to stay there till he is sorry, he will come off, take him back, he stays there when he stops yelling and says sorry he can come off, you have then taken back control.It would be a better idea not to walk in then say its bed time they could have finished their game and Dad could have told him it was bedtime. ,he was enjoying himself and you didnt give him a choice you told him. Walk in his shoes.....