potty training

my boyfriend and i just a had a baby together. she is five months old. he has two other children with another women there sonn is 4 years old and he refuses to go to the bathroom on the toilethe knows that he has to go potty he says sometihng to someone after hes a;ready gone in his dipar. his biolgical mother is dying of cancer and im going to be the role mom in his life howdo we get him to start using the toilet we have tired giving him treats and it just  dont work.. charlie his father and i seem to think that hes doing this because of his new baby sister please help us

[Kevin Kennedy, Ph.D.]

Sometimes children regress around toilet training when a sibling arrives, but they usually have alreday achieved toilet training. It sounds like your son has never been entirely trained - is that right? Adopt a positive approach, whereby you reward him for using the potty. Also, when he is at home have him sit on the potty at intervals. Pay attention to the time that he generally has bowel movements and you can plan around that to some extent.

[allmymarbles]

If you reward him for using the potty, he might get spiteful and purposely soil himself. Just a thought. When I trained my four children I simply showed them what they should do and made sure that the potty was always near to hand. (I removed their underpants so that there would be no delay.) I never rewarded or punished and was very laid back about the whole thing. I found that girls could be easily trained at 18 months and boys at two years. What I said to them was, "This is what grown up people do."