Abdominal Pain, Diarrhoea, Low Fever. Advise Medication
Thank you for the query.
Most likely his weakness is caused by dehydration. It is because he have had diarrhea for few days now. Fever indicates that this has been infectious diarrhea. Every diarrhea which lasts more than 48 hours needs to be diagnosed with stool culture tests.
As he is better right now (has no diarrhea) most likely he will recover without medical attention. Just give him plenty of fluids and keep him eating (mild diet is advisable). If no improvement, you should take him to the doctor.
You should also be aware of symptoms like increased heart rate (more than 100), low blood pressure, lack of urine. If any of this symptoms will appear, you should not wait anymore and visit your doctor right away.
Hope this will help. Feel free to ask further questions.
Regards.