Run away.
The only thing pegging the value of this company at $2.5 million is because the owner says so.
You can't determine a company's value without ANY understanding whatsoever of it's debts.
Who says he hasn't borrowed $4 million? Then it has a negative value.
Just because you see a lot of brewing equipment sitting there doesn't mean it has a cash value. It is HIGHLY likely every bit of it was financed, through many different sources that are hard to assess. He borrowed against his bank capital line until it was maxed, then financed equipment purchases from the vendors, then was slow in paying low priority suppliers, then put some on his wife's credit card.
Plus, used equipment is worth no more than $.10 on the dollar.
He is not selling value. He is asking you to share in his indebtedness.
He is trying to borrow from you because the bank (who is more qualified and experienced at assessing value than you are) won't lend him any more. Trust them.
I once bought another man's debt in the form of a coffee shop. Never more.
If you'd like me to prove my point, I can. Take it to the next level, and tell him you are interested, but need more facts. I GUARANTEE the next document he will supply you with is an equipment list. It will show model numbers, purchase prices, and values. It will look very impressive, and show a bottom line of the equipment value at or around the $2.5 million. This document is fake. Well, OK, it's not fake, but it is highly speculative, and optimistic. There are no established guidelines for creating such a list, and it is a standard practice for trying to impress a bank. Call an equipment vendor and ask them for a quote sight unseen.
If that is not enough and you want more proof, hire a forensic accountant. They will give you the same answer (with more facts to back them up). Their fee will be a small insurance for such an investment.