Proof of work experience

[byteme]

Hello. I've been working in a software company for almost three years(2 years full-time and rest is part-time). I started working there when I was in college.
The thing is my father owns the company. While providing proof of work experience documents my father's sign and approval will be needed. Are those documents going to be valid? Or am I going to need further proof? What kind of proof do I need if it is not valid?