i do like carmine as a character but as the sosu i just feel like there isn't much to say about him unfortunately.
he grew up poor and insecure and full of propaganda so he joined the military young in hopes of protecting his country and family, providing for his family and making his family proud. he ended up getting drafted in the war and after he came back he met nora, who he fell so in love with that it forced him to break apart his stoic hero persona that he was taught from a young age and expected to maintain by everyone else around him. not only was this refreshing and theraputic to carmine, only strengthening his bond with nora, but also nora had troubles feeling and expressing emotions and was also bottling what emotions she did have up. she found carmine uniquely charming though so he ended up being the only person who could make her laugh and smile on a regular basis which overjoyed carmine and gave him a sense of accomplishment everytime she was happy.
anyway they got engaged and had a baby and then the bombs dropped and upon losing his entire family and everything else he had come to know and love carmine reverted back to his tough guy persona to avoid his emotions but not before having a breakdown or two or three before leaving sanctuary. he ends up joining the brotherhood because it resembled a familiar militaristic justice that he had once found solace in and was the closest thing to "family" he'd be able to experience, ironically it distracted him from finding his actual son however.
after hearing about and promptly rescuing nick valentine his eyes started to open a bit to the injustices faced by ghouls and synths and people struggling in the general wasteland, he also grew fond of nick as soneone who could remember how things were pre-war. and also because he thinks nick is funny. he still has biases against ghouls and synths at this point however as he has not met many and makes assumptions based off of what the brotherhood says [[he'd definitely accuse nick of being an institute spy once or twice before actually getting to know him]]. he goes and murders kellogg dead with nick and the prydwen arrives and after being exposed to the heart of the commonwealth brotherhood he realizes they don't give a shit about actual injustices in the wasteland and are just sort of assholes. he still sticks with the brotherhood to an extent [[free decent power armour = hell yeah]] but shifts his priorities to the people in need and starts siding with the minutemen and invastigating the railroad.
he finds himself taking comfort in friends who have similarly lost many and/or important loved ones like nick, preston, and curie. he helps build settlements and establish community in the wasteland and others help him as well, insert louis wain "i am happy because everyone loves me" here. he slowly gets back in touch with his more emotionally vulnurable side as he is surrounded with new people he loves and trusts and lives happily ever after or something. the end.
correction: is there much to say about him? apparently yes. do i think his story is particularly super interesting? not really, i think it's a sort of basic story. but carmine is cute and awesome and has a nice personality i think so i like him anyway. i just have to hope other people feel the same way once i post more about him even if he isn't super quirky or unique in comparison to some other fallout ocs and such.