Illiteracy is the cause of poverty. We know a cup of coffee (Starbucks) = 20 notebooks, or a school bag, or two pairs of slippers for poor children in Vietnam.
The question is rather vague as bitcoin is no other than an asset or a currency depending on its use. Following this description, donating money/bitcoin can help poor children in general!
Why would an underdeveloped country develop a system wherein it revolves around a digitalized form of payment if most of their population are living under the marginalized sector? This would only lead to a waste of resources and money as it may be better if they diversify their expenses into enhancing their current infrastructures for job opportunities and employment for the people. Not to mention, you said it yourself! Being illiterate is common throughout the world and introducing them a complex system of payment would only add insult to injury.
Give donation in the form of money, clothes, foods, etc. so that their government would establish schools for the youth and NOT BITCOIN.