If your point is to animate the calculation you were provided by the physician than it doesn’t matter if Blender is free or not. It doesn’t matter if you animate it with Maya or Blender.
No 3D CG package is made for forensic material and realism. This argument from the opposition is not circling around Blender being credible but you being able to interpret and present the material correctly.
I could animate everything by hand differently in any application.
If you script the animation or better drive it with expressions which use Python in Blender, MEL in Maya and now also Python, then again it is not Blender that counts but the code and algorithm you scripted/wrote for the expression.
In particular when you have a spread sheet with key-frameable positions and rotations you can easily justify the animation compared to them.
Does the position really want to read the programming source code to see if in Blender they use fake math to make animation unpredictable - what a silly argument is that.
Do they wanna look up the unit system? This is pointless anyway because unites in cg programs and cad programs do not mean anything. they are virtual.
way more important is first that you can show them that the scene is modeled in proportion
cars, street and objects are correct.
then based on the spreadsheet keyframe the progress of the accident.
and present the animation in conjunction with the spreadsheet calculations.
Otherwise I think you have no way to convince them with Blender - while again that argument is silly and only a sign for a) their inability to understand how you would animate it and that the is nothing else than simple math behind it or b) they simply try to discredit you.