When your son damaged the HDMI input that could be part of the main board or part of a separate board. I suspect it is part of the main board so he did some damage that affected the entire TV rather than just the HDMI input itself.
If you are going to try to repair the TV you should google the make+model+parts to find what replacement boards are available.
Depending on the size, age, and cost to replace the entire TV it might not make sense to pay a tech to repair it.