Data collection is generally done as part of an evaluation. On average, evals take 60 days - depends on state regs. With the written evaluation in hand, the team meets and decides on support for the student (or not if they don't meet criteria to get help). Special ed level data collection would require parent permission.
Is the data collection & intervention trials part of RTI/MTSS where there are no timelines for placing support in place? RTI & MTSS are part of general ed intervention where data collection & support trials would not need parent permission.
If I was the parent, I'd be asking for a copy of the observation results report as well as requesting a team meeting to see what the next step can be. The school should have a 'child study team' of some sort that works with gen ed students who need RTI or MTSS. If this is a special ed eval, they missed the timeline for completing the eval & moving forward and a state complain can be filed.
Given how you have described this student, they need a special ed level of evaluation for learning disabilities. Having a LD & not getting the support you need can lead to frustration that comes out as punching classmates. The 'in your face' thing is the punching where this ends up being the school's focus and the root of the issue (the LD) isn't looked at. In cases like this, supporting the LD can fix the behavior. (Documentary, The Kids We Lose, covered this issue.)