Your experience with a difficult seller

My seller is demanding an unconventional and highly restrictive process and it's giving me hesitations to move forward and protect my time. Here are a few red flags: - He is operating without a broker and is asking for a 5x multiple on a $500k SDE business. The seller paid himself $300k every year, but the $200k of add-backs are questionable. - He initially refused to provide tax returns, bank statements, and legal docs until a Purchase Agreement (PA) was signed. I negotiated this down to post-LOI, but the initial hesitation is concerning. - He is asking we use his LOI template (which will require heavy redlining) and states he'll draft the initial Purchase Agreement for buyers to redline. - His LOI is heavily skewed in his favor. It demands paid training from Day 1, just two-years of non-compete, and prohibits the review of vendor, customer, or employee contracts during Due Diligence. - To my knowledge, no Buyer has yet to talk to the Seller yet, and will only get to talk to the seller post signed LOI. What's your experience dealing with a seller like this? Just from how he laid out the purchase process, he could be a good business owner and operates his business well, but I can also see him being a huge pain throughout the sales process.