welcome to healthcare magic..
wel from the above depicted history of ur son, its actually difficult to say if he lying or if there is some real problem..
the point which goes against lying is that he is going to bathroom quite often and for long hours as in that its difficult to find a kind who can malign so much..
in that age its very common to have mild on and off constipation
due to round worm infections...or it may be due to amoebiasis
in which there wil be alternate diarrhoea
itz better to give a simple and empirical treatment for that..
give him 1) ofloxacin-ornidazole
combination syrup once daily for 5 days and 2) as single tablet of albendazole
only once .. both the infections wil be cured... if the symptoms still persists then i would suggest you take him to a higher centre
wel i hope this solves ur query..
i wish him a speedy