I don't understand.......

The other day my SIL's son came all the way from Texas. Him and my SD are very close that every day they used to talk over the phone and pray together. The last time my SIL son was here (we even had a party for him) my SD was still up and running but she was already started to lose so much weight and she already felt pain in her right leg. This time, my SIL's son couldn't believe what he saw. It was devastating for him to see his cousin couldn't open her eyes nor talk no more. He was in pained. As we were setting around the table I vaguely heard him say " I don't understand". I was about to asked what made him don't understand but somehow deep inside I knew it but I opted not to say anything. The next day, Wednesday (i guess or Thursday?) we found out that he already left and by the time we meet my SIL and her husband at bob evans for a brunch, my SIL told us that her son is talking to him at the dallas airport already.
Me: Oh so he is in Texas already.
SIL: Yes by the time I talked to him this morning he was on his way to the airport parking lot.
Me: What makes him went home early I thought he gonna stay here for awhile.
SIL: He said he doesn't have anything to do here anymore and " he don't understand".
I said to myself this is it, this is the time I have to ask what made him don't understand.
Me: What made him don't understand?
SIL: He didn't understand about why D (my SD) who has a lot of faith didn't heal.
Me: (I pause and a smile came to my face) I think because God has his ways and plans. God is mysterious remember? If he is not mysterious and we all knew HIS plan then we are god too.
SIL: I don't like to be god.
Me: So do I.
And I started to share to her my faith when my mom was also dying. That sa kahuli-hulihang sandali na makikita ko ang mama ko I cling to my faith. That God will raise her from the dead and be alive again (remember the story of Lazarus in the bible). Until I humble myself, I surrender and let go my mother and let God do HIS will. That is when I felt tremendous pain so painful I was holding onto my faith and prayer and at the same time fear started to creep in.
That morning I was happy to share to her my faith and my experienced. For now, our family are still in limbo. We are waiting for her miraculous healing or the time she will be called by God to go HOME. I know it will be a painful moment for my hubby (when that time comes) but as I talked to him everyday he is somehow ready, he even says that we can't do anything when it is time for her to go. But I feel the pain of his voice as we all knew men are very good in not showing their feelings, so I encourage him to cry if he likes to cry he just laugh at me, but I told him I am serious!! That make him think hehe.