Ok am i right about this....?

my husband has children a son (16) i have a daughter (19) they both live with us.....my daughter had a child at a very young age the baby is now 2.....here is the problem....my daughter is now working has her own car and is a part time student going for her nursing degree...i am very very proud of her....during the time it took for her to attain all above mentioned things my husband would say you need to do this or do that and his son would chime in like when she took the written test to get her license it took her 3 tries but she finally did it....but all the while the hubby would say well you need to study more etc etc...it pissed her off bigtime but she bit her tounge i always stood up for her...anyway his son is now taking the written test (he hasnt studied at all btw) so i told my husband when and if he pes and gets his license i am not having him take MY car without him having money for gas all this kid wants to do is hang out with friends when i mentioned to get a part time job he freaked out and the hubby didnt say a word.meanwhile my daughter who did everything on her own......was bashed ...is this at all fair....why does my daughter get treated differently then his son........i have never treated my stepson any different then i have my daughter...any advice on how to handle this i am so angry about all of it.......