1. He was raised in his grandparents' because his parents couldn't afford to raise him. He totally understands it and still loves his parents.2. I hope you can be more understanding of him. He has done so much for you.
 (verb) understand (adjective) understanding of somethingunderstanding 很貼切的形容「諒解」或「體諒」
Many people in third world countries are living in nsanitary conditions.