I'm really sorry for your tragic loss Lu Xun. I understand how hard it is to loose someone very close to you. I lost a friend who was literally like a brother to me in October. He left behind a wife and daughter. I was so sad because he had cancer and we had many opportunities to visit him, but my parents didn't take me. He eventually died and I was left with the pain that I never saw him before he died.
I went through what you're going through. I tried to be strong, eventually I couldn't hold it anymore. I cried like hell, I'm a human too, I have emotions too. You got to keep strong and know (if it's your belief but it is my Catholic belief) that he's in a better place and looking on you and your family.
Trust me I know how bad you feel, like there's no one for you, that you've lost ALL hope and your left without faith. If you need anyone to talk to or any help, let me know. I'm here for you, even if you feel that no one is. Seasons will change and days will pass, but know you'll have to adjust to being without him anymore.
Now, just keep strong, it's going to be hard, but you CAN do it. I did it, I'm sure you can too.
Stay Strong Lu