Jin: Jin hates seeing Seulki cry. He babies her the most out of all the members and while it irritates her to no end sometimes, she needs it when she is upset. He can't always tell when she's upset because one of her specialties is masking her emotions. It drives him crazy to no end, but he does whatever he can to cheer her up. He'll cook her favorite meal, bring her hot tea, run her a bath, whatever she needs. He'll (quite terribly) braid her hair to comfort her and make her laugh. He'll tell his bad dad jokes and knows that she is on her way to feeling better when she starts laughing at them. Cuddling is a must and maybe a nap.
Yoongi: Yoongi is absolutely livid when Seulki starts crying, but he won't show it. He seems to know what all his members are feeling just by being near them. He hates when she hides how she is feeling because he can almost always tell when something is off. He won't ever force her to tell him what happened or who caused her to cry, but he will do everything and anything to find out in other ways. There is hell to pay when making his princess cry. Yoongi is more likely to get to the root of the problem and threaten it there before providing comfort for Seulki. He will never leave her alone though while she is that upset, always making his presence known in some way so she knows that he is by her side, always.
Namjoon: Seulki always seeks him out when she is upset. However, when she cries Namjoon is not always sure how to handle the situation. He is terribly awkward, but he does his best as her leader and her older brother. He'll hold her in his arms, kiss her head and run his fingers through her hair. He'll ask her about it, but he won't force her to tell him what is wrong. He'll stay with her as long as she needs or until she falls asleep and offer her the best advice that he can.
Hoseok: He hates seeing Seulki cry, absolutely hates it. He will jump on her and give her all the cuddles and kisses in the world. He'll do aegyo, dance, make noises, anything to make her laugh and smile. He won't directly ask her about what is wrong or what happened, but he'll subtly hint at it and she won't know until she's finally telling him. He'll watch her favorite TV shows with her or listen to music with her. If she's feeling up for it, he'll take her on one of their infamous ice cream dates, knowing that sweets can cheer anyone up. He'll absolutely insist that she needs to sleep in his bed that night just so he can make sure she is feeling totally better and if she refuses, she better make room because he'll be right up on her bunk with her, squishing her to death.
Jimin: Jimin worries tremendously about all of his members, especially Seulki. He wants no harm coming to his baby sister; physical or emotional. He'll hold her in his arms, singing softly in her ear and playing with her fingers or her hair until she calms down enough to talk to him. He won't force her to talk, but he also won't leave her be until she tells him what happened. Jimin is the scariest member when he's angry so once he knows who caused Seulki to cry, they're as good as dead to him.
Taehyung: Like Hoseok, he will jump up and give her cuddles a million times over. He doesn't like seeing Seulki upset. He is one that would rather take her out on a walk through the park or down by the Han river to help her clear her head and just get away from all the stress for a little while. He'll happily dance and sing or take her out to eat, whatever she needs. He won't directly ask her what's wrong, but he'll try to find clues as to what made Seulki this upset and handle it with his brothers without her knowledge. If he finds out who it is, any type of friendship they had or could have had is over and done with. When she falls asleep later that night, he will constantly be checking on her just to make sure she is comfortable and sleeping.
Jungkook: Probably the most awkward member when Seulki is upset. He is mostly used to his hyung's and Seulki taking care of him and offering him comfort that it's almost a foreign concept for him. He knows she doesn't like to be babied, so he will do his best not too. He'll set up his bunk so that she can come down and play video games with him. He'll run to the store and pick up all her favorite drinks and snacks, hoping it cheers her up just a little. He won't talk about it or acknowledge anything unless she does first. It usually ends up that she falls asleep curled on his chest and in between his legs while he continues to play video games and he'll smile softly at her, kissing the top of her head.