Why cant I get the phone to power on?

I have a friends phone that I am trying to fix. He mainly wants to be able to get his photos of his kids back. He told me it started with battery warnings on his phone and then he couldn't charge via USB-C port anymore. I have replaced the daughter board and battery with the exact parts from here but the phone still will not power up, even though my tester shows electricity going off all over when the phone is plugged in. No LEDs light up when plugged in either. Has anyone experienced this or know what I can try next? the front screen is in pretty bad shape too, not sure if this might help give insight for ideas on fixing it