C.,
I know what you mean about feeling like nothing works, epecially since they are so young and can't say how they are feeling. My son had a few congestions back at that age and I rubbed him down with Baby Vick vapor rub on his chest and back. That helps open the nasal area. I also used and still do use the vapor plug ins. They have Vicks vapor (STRONG) and they have a lighter version but it does help. Our son is in our room and it's a bigger room so if the vicks smell doesn't bother him then I would try that. I even like the smell myself of the vicks, helps me sleep better...
Being your son is 7 months old I can't say give him medicine they have for congestion. I have used the Pedicare congestion drops and they have helped, but my son is 2 1/2 years old.
Night time is always the worst for them sleeping.
Good luck, hope your little one feels better soon.
:)