Is this tolerable habit of my 11 yrs. old boy that his snacks in school is 250 ml of coconut nectar (Tuba)?

coconut nectar, or fresh liquid flow from the cut coconut flower encasement is very refreshing and nutritious though if one is not accustomed in drinking it or drank more than a glass or much. One would suffer diarrhea after about 2 hours but there would be no ill effect after than, just 3-5 times using the toilet.

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if this is not fermented yet, for those who are not aware of it, it is non alcoholic. No different from a freshly squeezed grapes and drank is not intoxicating.

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in islamic culture, there is a similar word that is quite confusing to the less aware folks.The tuba is most often confused to be only the alcoholic drink and not the freshly extracted juice from the coconut or nipa flower encasement. In arabic, nabeez is also confused by some arabs to be only the alcoholic kind and not the freshly pressed juice of dates or of other fruit. And in the quran, there states that in paradise,one of the rewards to be had there are rivers of wine. Some too excited misinterpreted it to be the wine itself but the whole verse should be understood, "in similitude" or it is allegorically emphasized is in the beginning of the verse. So, it is not wine or any intoxicants.

Perhaps the effects of Tuba is offset by sniffing Rugby ? Or Snorting some Horse ?

Tuba is an alcoholic drink. No matter how bad some schools are in the Philippines, I am sure they are not giving alcoholic drinks to school children.

I don't thnk you are referring to Tuba (alcoholic or fermented coconut water). If it's Tuba, he should be drunk all the time and not be able to excel in school. Maybe you are referring to the ordinary coconut water.

you should consult a nutritionist and ask an advice from him/her if that coconut nectar is advisable to your son to take that tuba everyday.

Coconut is healthy I don't see why there's anything wrong with it and if that makes your child a consistent honourable student then good for him.

Where I live, that is called child abuse.