Visitor Visa - B2

I applied for B2 visa for my mom and dad this month at Delhi Consulate and the visa got denied because of the profession of my dad. My mom is a housewife and my dad is working with my brother in his company as a director but he only manages the accounts, finance and a bit of the company operations part. All the other managerial work is handled by my brother. The company is fairly new and registered in 2019. Before being part of the family business, my father was a sole proprietor working in real estate dealings and constructions for almost 15 years. He also earns money from his rental properties. We are planning to apply his B2 visa application again in 3 to 4 months.
Is there a hope to get the visa? I am really disappointed with the rejection since my husband's parents and sister got their visas in one go. Is it risky for business owners to get a b2 visa especially when the business is fairly new? Also, should my dad explain his previous work in real estate when asked about profession?
I will appreciate the help. Thankyou.