Girls, I don't understand, am I doing something wrong? I don't use an …

Girls, I don't understand, am I doing something wrong? I don't use an aspirator for the baby, just rinse his nose with Aqua Maris Then nasal drops for kids called Nazivin, I drip them It's fine during the day, but when I do it at night, he lies down and everything gets clogged up, breathes through his mouth, although I did everything like that.