Different faces of grief

My mom has been depressed for the past two weeks. She misses Bangladesh, she misses my dad, she misses being able to pick up the phone and calling up her friends, she misses taking a rickshaw and going over to visit her family and friends. I've been trying everything I can think of to cheer her up. It's just not working. I am now getting depressed seeing her sad all the time. I miss my dad too, but I feel like I can’t really express my feelings to her because then it will make her even sadder than she already is. How do you make the pain of losing someway go away? It’s been a year and a half almost and I still feel the pain as raw and violently as I did the day he passed away. I can't even imagine what she feels like. I find myself trying to work longer hours so that I don’t have to go home and see my mom’s sad face. I feel horrible.