Two people both believe that there are 1,500 pounds of cherries in a truck. They agree to exchange the 1,500 pounds of cherries in the truck for $5,000. It turns out, through equal fault, that they were mistaken and there are only 1,200 pounds of cherries in the truck.
Aug 10 08:10:17 in the event BS&T goes bust, I have more than enough assets to cover that
In the event there is less than 1500 pounds of cherries on the truck, I have more than enough cherries to cover that, but if I don't - I will take your money?
No. If it turns out there aren't 1,500 pounds of cherries on the truck, then some equitable way has to be found to split the damages among the parties. If the money hasn't already changed hands and the cherries are still intact, it might make sense to just void the contract. But if some of the cherries have already been consumed or the parties have taken irreversible actions relying on the contract, then the harm done by the common mistake has to be divided fairly between the parties.
That's what I'm suggesting should happen here. Both parties made the same mistake which directly led to the harm and had the mistake not been made by both parties the contract wouldn't have existed, so the harm should be divided fairly between the parties. I'm not proposing any specific division as fair, but 50/50 would be my default presumption. (Actually, if Patrick expected to get a greater share of the profits than those he borrowed from, it might be just to make him bear a greater share of the losses.)