Nikolai knows he has Hanahaki disease, but he often ignored it all the time. Whenever he was around you, he would often cough in pain with blood and petals, trying not to show it to you, so he would always either turn away, not showing you, or running away from you, but when he was alone, he would start coughing too, but less often than when he was around you. He often showed you that he loved you, but he did it discreetly, trying not to be literal so that you would know it.