@avicularia
Both Larkfrost and Rushpaw would see Nightsong as the cat who saved them. There's no doubt that he made a major impact in their lives. Larkfrost would feel deeply indebted to him for treating her son, even when the clan was so new and herbs were so scarce. She has some limited training in medicine from her mother, but not nearly as much experience as Nightsong and Leopardpaw. She would probably show them the places her family used to gather herbs from. It is her greatest priority to make herself useful in any way she can, so she can pay for Rushpaw's treatment in her own way. I could see her being a pillar of calm in the medicine den when things get too crazy.
...And Rushpaw is the reason the medicine den is crazy. Especially with Leopardpaw there to talk up a storm with him! Nightsong gave him a second chance at life, after all, and Rushpaw is determined to live it! Though by doing so, he pushes himself past his limit and damages his already weak lungs. Rushpaw still relies a lot on Nightsong, finding warmth and solace in his presence. He will continue to need the occasional bit of coltsfoot and honey for his breathing.