I hate to be an echo but money is really the best way to go. Eventhough you may think she has "plenty" the mere fact she is working here, away from her children, should be a sign that money is a pretty major concern to her family. She's not working for trinkets, despite what that might say on a "personal" level to you. Every dollar spent in the Philippines is going to go much farther than what is bought here, and you give her the freedom to decide what to spend it on, which is the ultimate in respectfulness.