Hello! A two-year-old child was ill ten days ago. For the first coup…

Hello! A two-year-old child was ill ten days ago. For the first couple of days, mucus flowed, then just nasal congestion remained. I rinsed my nose with sea water and used Nazivin. And since then, for about seven days everything is normal, but in the evening, the nose is stuffed with phlegm, he doesn't sleep well because of this. He breathes through his mouth. It seems like it gets easier to clean, but as if the phlegm is somewhere far away that I can't suck out with an aspirator. Maybe someone had something similar, did they do anything? We're going to the doctor soon.