if he gets a direct sent off then fine him 2 weeks wages. repeat the same thing if he gets sent off like that again in the future and you'll see his aggression drop (A)
thats weird though, in my save, i did the same thing with vukojevic and his aggression dropped. maybe it varies with different players. anyway, try not to fine him if he gets a yellow then red. just give him a warning will do or he might become unhappy
Set his tackling to cautious, and isue warnings etc for dismissals. And if you have him on a training schedule increase the intensity of his dendensive training so he is a better tackler.
Hmm, maybe retraining him to stay on his feet when tackling a player could work. Theoretically it should reduce the number of reckless sliding tackles (should be the most likely reason for a straight red unless its a professional foul).