Sleepless Days

Ok i am 35yrs old a second time mom with 2 boys that are 12yrs apart, i know that all pregnancies and babies are different but my little Liam he is something else. He will be 3months on Saturday and he still only sleeps 2-3 hours at anytime day or night. I have tried night bathing, warm milk with oatmeal cereal and nothing has changed, ive even tried flipping (old wise tale). I'm not sure what to do, i would like for him to sleep at least 5-6 hours at night...everyone else I know their babies are just 2weeks-2months older then baby Liam and they sleep through the night. Any positive suggestions please!!! Signed sleepy mommy! Help!!!