Hi JB,
Post #2 here and the topics it links to also includes much more information about mattresses and children and “safe” materials including a link to some general guidelines for children in post #2 here. It also includes a number of links to the better forum posts and topics about mattress and children as well.
You can read a little more about the Arctic Dreams mattress in this topic. Children will generally do best with a mattress in the medium to medium firm range so I would confirm with them that it would be in a suitable firmness range (I believe that it’s in a medium range but they would know better than I would).
It certainly uses very high quality and durable materials which are unusual to see in its budget range.
The foams are also CertiPUR certified which means that they would be “safe enough” for most people.
Overall … as long as you can confirm that it would be in a suitable firmness range … it would certainly make a great quality/value choice.
Phoenix