Stinky, frequently passing tough stools.

Dear Doctor, my son is 6.6 years age. I m observing the problem since couple of months. He is passing hard stools every 10-15 mins in the underwear with soiling of underwear not large quantity. But observed his stools are very tough to pass and he is struggling to pass. It has become a worry now, bcz he is living like that since more than a month now... My kid have speech delays and cannot communicate his pain. Please help what should I do to rescue him from that painful stools or frequency of soiling underwear. He am managing good water intake but the problem is fruits he does not eat which i m practicing to give him in various methods. Please suggest to Clean his stomach and then maintain his healthy lifestyle. Thanks, Durga (mother of Karthikeya, the child i referred in the above context)