You need to get more experience.
Not really.
Most online casinos weren't made by one person. He needs a team, at the very least a partner and they need to hire a team.
For instance, he has some coding background, so let's assume he learns a bit and covers backend dev. He needs a front end guy, possibly another back end with experience in crypto wallets, unless they want to handle all deposits/withdrawals manually, in such case he needs someone trusted to manage the wallet. He'll need someone to handle all the advertising and promoting, someone to take care of support.
You have almost summarized everything in your answer.
- Since he has programming experience, he will need to develop that experience to be able to supervise the development process of the platform’s programming, including improvements, additions, and updates. This does not mean that he does the work himself, but at least improves his skills to be able to supervise who will delegate him to carry out the task, which is preferable to be a partner and not an employee, at least at the beginning of the project.
- He will have to use one of the payment gateways to supervise the withdrawal and deposit operations to be done automatically because doing this manually will cause a lot of time to be wasted. This is until it is possible to program a payment system for the platform without the need to purchase the service from automated payment gateways that may not provide sufficient support when needed. Of course, the owner of the capital is the one who must fully control the hot wallet of the platform.
- For promotions and advertisements, the best place to do this is the Bitcointalk forum, but you need to hire a trusted moderator to do these operations. This will increase the credibility of the platform and increase the demand for it.
Finally, with regard to the support team, support workers must be assigned to cover their work shifts 24 hours a day, provided that their supervisor is in direct contact with the other three departments: the development department, the payments department, and the advertising department. This will help them respond to users' questions and help them overcome difficulties while using the platform.