My brother works in a timber factory and has a work-related injury. Now the boss doesn't admit that my brother is his employee, so he has hired a lawyer.

This evidence is enough. It can be proved that your brother is an employee of this unit. If the opposing lawyer denies the authenticity of the time card, they need to prove what the time card of their unit is like and how it is different from the time card you show. It is also necessary to prove the authenticity of several time card photos put together by company employees. It's not that easy. The court will also conduct an investigation among workers and finally confirm it. You don't need to worry too much. What you have is enough, and the court will certainly accept it.

The recording does not need to be printed, because the recording itself is a kind of evidence of "audio-visual materials".

If the unit does not admit it, their results will be miserable. You can also report to the local human resources and social security bureau. Anyway, you are already in trouble and don't plan to do anything there, so let them accept administrative punishment. The unit certainly didn't pay work-related injury insurance for your brother. That's enough for them.

Together with the administration and the judiciary, they killed these black-hearted guys.

The specific amount of compensation can be calculated after the results of work-related injury appraisal come out. Look at the Regulations on Industrial Injury Insurance, which contains calculation methods. You can find it by searching online, which is very convenient.

Don't worry too much. I wish your brother a speedy recovery.