He's just chill now cause his body constantly built up "poison" before and he had no way of getting it out, his body was under a lot of stress and he's just naturally very anxious. He barely got enough sleep and felt very lonely since he felt no one in his entourage understood him, amongst siblings with the same gender as him he is the only one capable of emotion, I believe it's implied that a DA with feelings can be unstable, probably why they have to be "sociopathic" according to the author, maybe it's to make survival easier since they can't get emotionally attached or be reactive if they need to survive (remember how he almost shot people at the beginning, he got emotional too quickly, while Grayson or Keith would have most likely reacted differently.) Ml is an exception. Now that he is able to get the poison out, rest and feel safe by also having someone to honestly talk to he has chilled out. Also, he's got a crush on the mc, knowing how the mc is, he can't impress him by being rude.
his personality still shouldn't change so quickly like that healing takes time and it happened right after he got prescribed those new meds by that weird doc and got saved by the mc and i understand that he might trust him more after getting saved but he became so submissive after that
how tf did ml become so submissive i can't be the only one that feels it was a bit unnatural right!?