Forever .

I agree with my colleague. You are going to have to do some legwork

Will it stand WHAT? You may get subpoeaned. If you do not appear or do not testify you may be held in contempt of court

Before you do anything you should speak to his attorney

The police are trying to get incriminating evidence against him; they are not trying to help him He has no obligation to go or talk to the police.

You can choose to not go to that doctor

I suggest that you read articles on the definition of hearsay. Direct testimony by a witness as to something happened is considered substantive...

This is personal injury, not civil rights, as the question does not involve any alegation of wrongdoing by a governmental body

There is no way anyone here can make that determination

I suggest you start documenting this situation with something more than your word., like photographs and recordings