I don't like him!!!

So my sister and I were having a conversation and she asks me this question.... omg 😲 do you like my boyfriend??? Like him as a person. Me being very honest, I replied no. She went on to ask me why.... I reversed the question asking her why do she like him... she was like no I asked you because it seems like every time he say something to one of the children you look at him like shut the f&&& up!!! That's very true. I flat out don't like him. I try to civilized for the children but that super sorry mofo needs to kick rocks for real. I just hate it when we women settle for losers when there are so many amazing guys out there. I'm not dogging her dude out just because but this dude is pathetic. He doesn't support her nor the children. My mother and I support the children when financial support is needed just because we don't want to see them without. She's been in this shitty relationship for 6 years I know. No progress made on his part. She lives with my mom, three children, and guess what???? He lives there as well. No contributing to anything. She's always saying he's trying to do better.... 🤦🏽‍♀️whenever he comes around he whole spirit changes. I'm trying to remain close to my sister but this loser ass dude is driving a wedge in between us. Do you think that I should tell my sister the reason why I don't like him or just leave it as is? She's not going to like me if I speak my mind, for real... I want to see her truly happy 😊. She so deserve it! And I have a man, who makes me happy 😊