Tanjiro:
Tanjiro goes full Mom Mode and starts soothing you, letting you hug him and cry. Usually he can get you to stop crying in at least five minutes. If it's something so awful that you just have to cry it out, he lets you, running a soothing hand up and down your back.
Nezuko:
Nezuko hates seeing you cry because it makes her feel like crying, especially if she doesn't know how to help. Usually she hugs you and tries to calm you down the way she sees Tanjiro do it (and sometimes her memories of being human come back and she may mumble soothing words to you through the gag). Sometimes she'll even cry with you, and you both end up curled together asleep.
Zenitsu:
He gets the Big Sad with you. If you started crying in front of him, he's so distraught for you that he often starts crying with you. You two end up holding each other, whether or not he's sobbing with you.
Inosuke:
Inosuke doesn't really know what to do when you cry in front of him the first time. He's stunned for a little bit and will tell you to stop, but if you don't stop he kinda panics and goes to Tanjiro, demanding what to do. Then he may go to you and let you curl up against him and cry it out. It makes Inosuke uncomfortable, but he wants you to feel better, so usually he'll try to do something stupid to make you laugh.
Giyuu:
Giyuu is awful at comforting people (hello, mister trapping-your-feelings-in-a-box man). He'll usually be awkward about it, trying to calm you down from a distance (and failing horribly). Depending on his mood, he may hug you tight, letting you cry it out on him. He hates seeing you so miserable because he doesn't feel like he can do anything to help. On rare occasions, he may cry with you, self-loathing and the feeling of being useless to help manifesting as quiet tears.
Kyojuro:
Kyojuro knows just how to calm you down, because his younger brother cries a lot. Usually he takes you into his arms and soothes you with something funny, like a joke that Shinobu told him or a funny story of some sort. He may make you some comfort food and you eat it together. Sometimes he may even get Senjuro to cheer you up by being himself (it has about a 90% success rate).
Muichiro:
Muichiro kind of freezes up when you cry, mostly because he's not used to being on the other side of the coin. Usually he tries to do what he remembers his parents doing. Often he takes you to sit somewhere peaceful and curls up to you, letting you cry it out. Sometimes he tells stories about his family, which makes him cry (and you both end up kinda sobbing about your families together).
Shinobu:
Shinobu doesn't fully know how to deal with you crying. Usually she just lets you cry it out on her shoulder, but sometimes when she's feeling extra frustrated she'll cry with you. She may try to make you laugh by telling you funny stories about others (usually Giyuu), or she may show you the triplets (Sumi, Kiyo, and Naho). They're sweet enough that they usually work to cheer you up.
Gyomei:
Gyomei usually cries with you. He'll hold you close and you both will cry, letting out your emotions. He'll sooth you by running a hand through your hair and telling you about the temple children and how sweet they were. Sometimes the cats will see how you're feeling and will curl up in your lap, as much as five at a time (they're very affectionate).
Sanemi:
Sanemi hates seeing you cry, because it reminds him of Genya. Usually he'll start out by asking you to stop, but he'll end up holding you close (sometimes crying too, mostly from the memories of his family). He gets incredibly gentle in those episodes, especially if you fall asleep on him.
Akaza:
Seeing you cry is uncomfortable for him, so he usually tries to get you to stop or cheer you up by awkwardly wrapping an arm around you and pulling you in close. He's pretty gentle in these moments, because he doesn't want to accidentally hurt you in any way -- he thinks it incredible that you trust him enough to even be this vulnerable in front of him and he intends to keep that trust.
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A/N: I had to look up Muichiro's twin's name and I started crying again because hey hi hello, thanks I hate literary parallels! Also, I know the butterfly girls aren't triplets, but I've had that nickname for them ever since I first saw them and I regularly forget their names, so just calling them 'The Triplets' works better for me, lmao.