My Baby Grandson Used To Pass Stool Normally Until He

My baby grandson used to pass stool normally until he was over a month old. Then he started passing stool after two days or more but stool will not be hard. Now he is three months old. He would not pass stool 4 to 5 days or more then will start crying a lot and pass gas with very bad smell. Still will not pass out stool until some stimulation is done in anus. The strange thing is the stool will be loose nearly watery.