Amex runs an on-line bank that offers significant credit lines to "small business" as an extension of their credit card services. Its usually not the best or cheapest option.
Overall he would far better offer establishing either term loans or revolving credit with local banks. Rates, service and amounts would be better. Its possible that some banks in leftist MSP would not want his business, but there still should be many local and regional banks who would be interested.
If banks are truly that politicized, he could even do a private debt placement with wealth investors. If his business is solid, there are many wealthy conservatives who would likely support him.
I would love to see the "My Pillow" books and spend a day with his management team. I suspect there are financial issues with his company that are turning-off potential lenders. The cause could very well be political revenge, or it could simply be poor management, or some combination. IDK.
That may not be an option right now. Many of those right now are pulling loans to pay dividends.