Since how long he is having these symptoms?
Is there any runny stuffy nose associated with it?
Is there any vomiting or diarrhea involved as well?
please provide ore detail.
If he is having diarrhea with low grade fever, I will suggest to give him more oral pedialyte that will help t replace fluids and electrolytes those are being lost because of diarrhea.
Apart form that he can also be given rice cereals , banana to help regulate his bowel movements.
Please do not give him apple or orange juice as it will worsen the diarrhea by osmotic effect.
For fever give tylenol or motrin and dose should be based on his current weight.
In case it gets worsened, then he can be seen in local emergency room otherwise he can be seen in the morning by his pediatrician.