The Music Of Healing is a Tommy Sands tune. It's a little old for 4th graders but they might grow into it. Down By The Riverside is always a good idea. The Hebrew song about swords into plowshares or (something else...what is it Mudcatters?) "It Could Be a Wonderful World" (not the Louis Armstrong cover tune).

If we could consider each other
A sister a friend or a brother
It could be a wonderful, wonderful world
It could be a wonderful world, oh yes,
It could be a wonderful world.    Written by Les and Hy someones.
From a compilation called "Little Songs on Big Subjects".

I'll try to think of some more.

Frank Hamilton