How to convince elderly mom/pop to share verifiable income/expens

[Jay Helms]

I’m working with a broker to acquire a mom/pop owned Mobile Home Park (36 pad), sellers are an elderly couple. Had the property under contract for several weeks and one excuse after another (waiting on CPA to get past tax season, had to go into the hospital, I just don’t want to share my financials) the sellers have not and seem to refuse to provide verifiable income and expenses. 

What are your ideas to warm the owner’s up to sharing veritable financial info?