Wow . . . a lot of emotional decisions to make, on which I am no expert.
On the business side though, my suggestion is to run the existing company, turn it into something great and then sell it and fund your new idea. Remember: The biggest challenge with running a family business is the question of whether senior family members let you run it as your own.
If not, then go do your own thing.
From a pure financial viewpoint, you will generally make a lot more money a lot faster over-hauling an existing average business than you will starting something from scratch.
All the Best
Brad Sugars is the founder and chairman of ActionCOACH. As an entrepreneur, author and business coach, he has owned and operated more than two dozen companies including his main company, ActionCOACH, which has more than 1,000 offices in 34 countries.