How to claim the labor rights of late father from employer who refuses to pay?

My father has passed away in Pakistan after serving 17 years in a private company in Dubai. The company has refused to pay his gratuity due to a lack of funds.

In case I need to apply for a labor case, what are all the documents required?

My father had two wives, my mother being the first wife and my stepmother (currently living in Morroco with my two young stepsisters) and both of them are out of the UAE.