A business that started since 1960? Wow, I can't believe this, your father must have been a very good manager but your brother not being a business minded person has failed to continue with the affairs and you joining now it's time to show your managerial skills.

Developing customer relationship is very necessary in any business and I am sure continued to maintain the customers you had already.

Before expansion, I agree that you should look into the state of the business first and looking at your business, the only expansion I feel would be good enough is letting your brother have his own business while you have yours, after all, it's part of expansion.

Good luck to you!