Like a child's puppy love. If we stop them blindly, it will only make them worse. It is best to give correct guidance.
Suggestion:
You can also join your father's interest, communicate with him first, and make your father feel that you are on his side, so that he will listen to you.
I'll start reading some introductory books on the stock market. I suggest reading more catalogs. The general catalogue is full of famous aphorisms, which is very helpful for beginners' mentality.
Introduce your sensible books to your father, and you can create an account with a small amount of pocket money to play with your father.
Start discussing the profit and loss of the stock with my father, analyze more and communicate more. With normal guidance, it is not easy to get deeper and deeper.
The stock market does have risks, but the risks can be controlled. You can play the stock market, but don't get addicted. Don't invest all your property in the stock market. Don't blindly deny your father, but you must control his gambling, let him invest reasonably, treat the loss rationally, and imagine the loss as a cost, which is inevitable but controllable.