Relieving And Preventing Foot Pain?

My husband works sanitation at a factory, 12 - 16 hours a day. He is constantly standing, wearing big rubber boots. He recently bought some cheap insoles from Wal-Mart hoping that they would help and they do, but not as much as we were hoping. Any advice on the best insoles or things he could do at home to make his feet feel better? It is causing pain in his feet, legs, back, and neck. Any ideas would be useful. Thanks in advance!