Hey there.

No, that's not really a lucid dream, as you were not aware that you were dreaming.
However, some logic part of your mind seemed active, for you noticed that your grandfather can't be there and alive. Unfortunately, you didn't conclude that it was a dream, but were shocked (and woke up) instead.

I suggest you browse these forums and read some tutorials, lucid dreaming is a very interesting topic.

Happy dreaming