I believe that one thing does not take away from the other. It is good to ask the question in this forum as general information if he is thinking of opening a casino, but if he decides to do so and is serious about it, he should consult a lawyer.
Not just consulting any lawyer, but seeking legal counsel in the country he wants to establish the casino company is very important. I think he can also get good advice from other successful operators of online casinos in the area. They might be able to give him the necessary advice because they have the necessary experience.
I also agree with the majority. If I were to open a casino today, I would do it by acquiring a licence. Although technically it is possible to do it without a licence and there are still some casinos that operate without a licence.
Although licensing might not be a true test or benchmark to certain the genuineness or quality of any business before I transact business with any firm my first observation would be to confirm if the company has the necessary license that empowers them to operate in the business or area. It has a way of giving users confidence that the business is safe. And I am sure a licensed casino would attract more customers than an unlicensed one.