I too am sorry for your loss. My grandmother committed suicide when I was young. It took my mother a long time to accept it and to not blame herself. She felt guilty that she hadn't done more to help her and to be there for her. She finally realized that there probably wasn't anything she could have done. Being young, I had always felt a peace about it, because I knew Grandma was physically sick and psychological distraught. I have always felt she was at peace afterwards. I definitely miss her, but I like to think she's got my back when I need it.
As for why your father did it, you probably never will know. Everyone is different, but I can relate how I felt when I developed postpartum depression. I felt like I had an unbearable weight on me, like the Wicked Witch of the East must have felt when that house fell on her. I felt like I was constantly sinking. I thought people were against me and saying things about me, despite the fact that many people said the exact opposite. Being away from people helped, because it cut down on what just seemed like constant noise and chaos, so I pushed people away. However, being away from people dug me further into that deep hole. I just felt unbearable pain and stress, like I was running a marathon that would never end, unless I died. I didn't want to hurt anyone else, and I wasn't being selfish. I just wanted the pain to stop and to quit being a burden or harmful to my loved ones. In the end, I got help and didn't commit suicide, but I think many people are not that lucky. I remember wishing that someone would realize that I needed help, because it was hard for me to admit it. Plus, it was difficult to tell if my perspective on things was even correct.
I hope you eventually find peace and solace, and I think this trip is absolutely necessary, especially if there are things there that remind you of happy times with your father.
Now for the the happy stuff
Your trip sounds awesome! Jiko is fabulous. One of our favorite restaurants at WDW. That's great that you are getting the dining you want and mostly the FP+ that you want. Just remember to relax, slow down, and enjoy the little things that you might normally look past. I am looking forward to reading about your trip. Also, I find when I feel bummed or stressed that listening to Disney music helps. I usually listen to Mouse World, but lately I have been listening to Subsonic. Nothing can make me smile like hearing the MK Main Street background music.
When I told him I was able to get the Minnie's Holiday Dine though he just about jumped out of the shower with excitement - I couldn't wait to tell him so I ran in there... 
It's crazy busy! Good thing we have our fastpasses and our main goal is really just to see the lights. But, on that note. My husband and I were discussing our Friday morning plans of heading to the Beach and Yacht Clubs for breakfast and decorations... we've cancelled that portion of our morning. We want to get to the park pre-rope drop to make sure we get through security in a timely manner. I was hearing that it took some people at MK two hours to get through security. DHS is open 8 AM - 11 PM so that means we want to at least be at security by 7:30 AM. I don't mind if we get in right at open since we don't need to run to any rides... I just want to be in. So then I can get in line for my Starbucks even earlier and maybe beat that rush. 
Overall a wonderful trip - but I don't want to give anything away! Stay tuned! 
I actually just moved up to Grafton but was initially searching for a place in Cedarburg. I couldn't find an apartment that would allow two clawed kitties and had a washer/dryer in unit though. Love Cedarburg! 
