When DS1 (16) got up today he started arguing with me because DS2 (8) was eating cereal that apparently he wanted (DS1 never eats breakfast btw so I didn't know this). He then told me to fuck off and went to his room, DP then went to talk to him and DS told him that his girlfriend broke up with him and he wanted to be left alone, so we did.
This afternoon DS2 was playing swingball in the garden and DS1 then came downstairs and hit the ball quite hard and it hit DS2.
DS1 said it was his own fault and that he should've hit the ball. DP took DS1s phone off of him as a punishment, DS1 then pushed him and told him to fuck off and that he isn't his real dad (he isn't but he doesn't see his biological dad and he's raised DS1 since he was 4). DP then pushed him back (not forcefully) and told him to grow up and stop acting like a spoilt brat.
DS1 thinks DP was wrong to push him etc but who was BU?