Ok not really sure WHAT this would be called. Oldest SS who is 20 now was thrown out of our house when he was 17(long story) and has NOT had any contact with DH since. Older SS went to live with BM when he was thrown out at 17. Older SS20 was adopted. SS13 is not. Both step kids know this. 

Younger SS who is 13 maintains a relationship with Older SS20. DH will make comments to SS13 about how Trampy SS20 girlfriend is and tell SS13 to stay away from her. DH will tell SS13 he better get his grades up or he will end up like his older brother. When older SS20 moved out of BM house to be with GF DH made a comment it must be nice not having him in the house anymore. Think you guys get the point..

Now I don’t THINK DH is Actively trying to get SS13 to hate SS20 BUT he is Definitely giving the impression he thinks SS20 is a total loser and glad SS20 is no longer allowed over. 

SS13 will “play along” with DH and sometimes act like he does not like SS20 but I think he’s just telling DH what he THINKS DH wants to hear. 

DH sees nothing wrong with what he is saying to SS13  about his brother saying it’s no big deal. I tend to disagree. No big deal or wrong?