Retail business system improvement

Good morning! Our family business is selling construction materials. It's been our business since I was a kid and up until now, I still dont know much. I always see my parents working hard, my dad wakes up 6AM to open the stores, theyre up until 10pm or 11pm checking daily transactions, they stay in the store to see the operations everyday for 7am to 5pm, they couldnt go to long vacations when nobody would be in our store, in short, they're tied up on the business. Dont get me wrong, they earn more than enough for us, I feel blessed and contented. I just want to have an idea on how big businesses like Wilcon or Ace Hardware does it, the owners arent there but I think theyre doing fine. We currently have inventory system from a not known company and I think theres still many flaws. Since I'll be taking over this business when time comes, I would like to ask if there's a way to manage the business more efficiently that we can have a little free time. I'm thinking of a good inventory system, accounting system would help us with our problem. If I can find solutions to this, we can expand more (we currently have 4 branches) without adding much workload (main reason why my parents doesnt expand).