Their donation will go towards vaccinations administered by Save the Children.
The UK was ranked 23rd in the annual Mothers' Index compiled by Save the Children.
Only three other countries categorized as "more developed nations" by Save the Children, rank lower: Albania, Moldova and Russia.
The tents provided by Save the Children, swelteringly hot inside, are still unfurnished but for a few school desks.
Meanwhile health workers supported by Save the Children run clinics on a shoestring in remote villages, administering vaccinations under trees.
The boy who was tied up had been identified as a "vulnerable minor" by Save the Children.
(Interview facilitated by Save the Children) Sukainah Ibrahim al-Shdiefat is head of a school in Jordan's Zaatari refugee camp.
The Facebook post by Save the Elephants about his recovery attracted more 200 "get well soon" comments.
"We heard gunfire, Kalashnikovs, cannons, all that," said one 11-year-old, interviewed by Save the Children.
