I was surprised how someone will plan with money he is not sure of.
I don't see how it was surprising. What do you want then? Just plan afterward? As you mentioned, he is a professional gambler and already achieved around 80% of his plan. Therefore, your friend was motivated and his approach to gambling is really good.
Maybe with those plans, your friend takes that as an inspiration to do his best, and fortunately, he's on the good track.
In my case, I'll just go with the flow with my gambling activity.
Usually everyone agrees that in gambling everything depends on luck (and not on your mood or skills), and the advantage is on the side of the casino. Thus, in the "normal/average" variant, the player gradually loses money and does not consistently earn it (which is generally a rarer case than even the jackpot). Thus, it is quite expected to be surprised that someone plans to spend (and seems to really spend) the money that he earns on gambling.