I'm so sorry about the loss of your grandfather. Sometimes it seems that the timing of things in life is so off, but I believe everything happens when it does for a reason. But I totally know where you're coming from when you talk about the anxiety of a trip.
Last year, we were supposed to go to WDW in June. In May my grandfather was hospitalized unexpectantly, and we discovered he had a very rare brain disease (1 in a million chance) that had no cure. We decided we didn't want to chance being in Disney when he died. He was scheduled to have the feeding tube taken out on June 23--the first scheduled day of our trip. He finally died on July 9, so it wouldn't have happened on our trip, but we would have thought about it the whole time. We rescheduled the trip for October.
In October, we were all ready for the trip. Then my mother-in-law found out she had to have a knee replacement. She was in so much pain that she couldn't put it off. She is not in very good health so there was extra risk involved. She scheduled it for the day before we were to leave. Yikes! I was like "Here we go again." But she talked us into going on our trip because she was going to be in a rehabilitation facility for the week after the surgery and she said she would need us more once she got home. We ended up going on that trip, and everything went fine.
This year--We are scheduled to leave for HHI on Monday. I've been thinking "What's going to happen this trip?" So I know what you mean about feeling that way. Well, my father-in-law found out he had to have open heart surgery to replace a leaking valve. He had it last month though and has recovered well. I'm thinking everything's going to be ok, we'll be able to take the trip. Well, I shouldn't have gotten my hope's up because yesterday I found out that he has to have prostate surgery ASAP. He was released from his heart doctor so he's free to have the prostate surgery now. They schedule the surgery today. So I won't know until later today whether we will get to go or not.
I'm starting to learn not to get excited for the trip until I'm actually on it. But I totally believe that everything happens for a reason. If something happens to prevent my vacation, then it was meant to be that I not be traveling at that time. God always knows best!
I definitely think you should continue your trip as planned and have fun! As far as future trips, just don't think of it as a jinx; just think of it as it something that is meant to be. My prayers are with you and your family.