Although your video memorial is encapsulating an entire life, it has to engage the viewer. Attention can easily wane when a video is too long.
A single music track is the ideal length.
Maybe it is better to ask: "Why put the burden on your family, when they will be dealing with grief, stress and limited time?"
You save them the stress, by preparing in advance.
You get to relive and celebrate many wonderful moments of your life and how you want to be remembered. You get to decide what music, images and memories to convey to your loved ones.