Not really sure what you are asking here there than some general advice. It's not specifically about PAYE and Ltd company as your title suggests. For what it's worth here are some pointers as I see them from reading your post.
1. No one likes being unemployed so I understand how your husband is feeling.
2. If the current shop business is working, although it may not be making profit, if it is covering all the costs then it is a working business. Many lifestyle businesses are run for the benefit of the people working in them (usually family). So if a wage is being made it is sometimes more important than profit and dividends. Now whether there is a job in it for your husband only he and his brother can tell. It will mean someone already working there will have to go because it is only covering costs at the moment. Alternatively there may be growth in the business maybe your shop specializes and can sell online or door to door, there are often other options if you are doing something different.
3. If your husband and his brother are employed in the shop then it is proper to do it PAYE employee basis. There may be some advantages to sole trading or partnerships but if all goes badly then limited liability protection may be valuable. Only you can tell on the long term viability of the shop and the products you sell.