A good start, but safety is a process, not a task. It is continuous and ongoing.
No high water alarm.
He did not notice that the boat "felt funny" even with 4 ft of water in the bilge. Lack of situational awareness. Pay attention. If it "feels funny", there is a reason. Check it out. Note that "the Captain" is actually always "on duty" when aboard. OCD can be your friend.
Planing ( and training) is important. When things are "good", run mind exercises asking "what if..." and analyze your response to the hypothetical issues. Do this frequently. You may never be perfect, but this type of planing will go a long way to minimizing casualties.
There is more, much more. but he made a start, which is positive.
Always assume that a boat, from the day ( before! ) it is launched, is trying to sink. It is your job to make that less likely.