Help with 3 yr old not sleeping!!!

Chase is having trouble sleeping through the night. He is snoring like a bear and even Benadryl will not get him until morning and only makes him stay asleep a little longer instead of helping him breathe easier. We tried a humidifier but did not notice a difference and he did not like the noise of it. Vicks vapo rub did not do anything but make him cough. He awakes in the middle of the night and comes in our room and takes up his snoring in there. Sometimes I go sleep in his room. Please help this Mom get some sleep and this little one breath easier! Thanks so much