Your boyfriend hasn’t asked you for help with money. It is best that you don’t offer it at this time.
He is trying to find other ways to pay back this person that he borrowed money from.
If you were to offer him money at this point in time, you could open the door to future requests for money from you that could end up putting a lot of strain on your relationship with him.
His shop is going to have future expenses that need to be paid. If you give him the impression that all he has to do is come to you if he has to purchase or fix something for his shop or has a shop-related bill, he may decide to take the easy road and take advantage of that.
Your boyfriend did not start this shop with you. In essence, you aren’t his business partner. You do not owe him anything.
For now, let him go about solving this monetary issue on his own. It will help to build character and keep him from looking to you in the future to help him with shop expenses.