Your experience in your family business will count, although you should detail your contributions and what you learnt from your experiences. In general, MBA admissions teams like to see work experience after graduation, however some business schools (Harvard and Stanford for example) do consider younger candidates.
With regards to letters of recommendation, asking a family member of any kind for a letter of recommendation is definitely not suggested, so you will have to be creative and think of other options. Some options for people you can ask are: employees, business partners, board members, mentors, clients, strategic partners.
I hope this was of help. Please let me know if I can answer any other questions.
Conrad and the Stacy Blackman
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