How do you tell someone that you don't think their plan is going to work?

I'm really in a tough situation. We have four weeks to move. And the days are counting down. My husband is interested in buying this business. But he will have to travel five hours in one day (there and back) to work from where we are now. We need to find a place quickly to move into. Things are tight trying to move to an area where we are at locally. So moving two and half hours away is not reasonable in the time frame that we will have to move. Our landlord needs us out by September 1st and there is no talking to him about that. He already asked if we could be out before that because his wife would like to have the kids in school but that is just not financially possible for us. Some how my husband needs to see that if we try and do what he would like we are going to be out of a house. The business situation is just not reasonable at this time. How would you tell your spouse something like that? I think I should have his grandma and great grandma talk with him about it, because he will just think that I'm not being reasonable.