It is actually a requirement of all countries (not just Dubai) that you carry a copy of the prescription and/or a doctors letter if you are taking prescribed meds into any country.
I don't know what the meds are or what they are for (nor do I need to know) but this applies to all countires and to all prescribed meds.
The reason for this could be that the meds your son needs may not be available in another country in the same dosage/formulation or just simply not available at all and it will help a medical person, especially in a life threatening or emergency situation to know what medication is required or alternatively what other medication can be combined with what a person already takes.
Medical practioners can then prescribe similar or alternative treatments if necessary and also know what not to give a person in the event that they or their family are not able to assist by recalling the name of a drug they are taking.
For this reason, prescribed meds should always be carried in hand luggage and not in a suitcase that can go astray.
So it isn't unique to Dubai but people fuss more about Dubai because of the perception that they may get stopped at customs and thrown into jail - highly unlikely if you are doing nothing illegal.
The reality is that taking a copy of the prescription and/or a doctors letter together with carrying the prescribed meds in your hand luggage may safe a life
Edited: 5:58 pm, March 30, 2011