My son is congested and I dont know what to do?

and has been for a long while now, the doctor said it would p but it still has not, and I feel really bad for him. Its winter here and about 50 degrees outside so he doesnt go outt oo much, but Im not sure if the fresh air would help him. I suction his nose pretty much all day, but it never seems to be enough. He is almsot 6 months old and I dont know if there is anything I can give him but we have tried everything but medicine (humidifier, going outside, hot steam). I am pretty sick of the doctor saying it will p. Its been almost 2 months already. What do you think?