MacBook Pro 13 2015 A1502 Keyboard and trackpad no longer work

I see multiple postings about issues with keyboard and trackpad that stop working on the MacBook pro 13 2015 A1502 but nothing in those posts worked. I need some ideas and help.

Background and worked performed to date. My sons school laptop keyboard and track pad started acting up over several days while using it normally and all together stopped working. I did OS updates first hoping it was software related and that didn’t fix the issue. I did web searches and I read the forums here and other places and tried resetting the SMC and PRAM as the second step. I then ordered the ribbon trackpad cable and replaced since that fixed the issue for many people. It worked once then stopped working again without even getting the screws back in place. I then replaced the trackpad with a new one and that didn’t work either. I then took it to a local Apple repair store (Not the Apple Store) and they proceeded to replace the top case, main logic board, trackpad, trackpad cable, and even the ssd with zero success. They tried different combinations and the MacBook still doesn’t have a working keyboard or trackpad. they gave up and said they have never not been able to fix a MacBook problem before.

The laptop works fine with USB keyboards and mice and you can sync Bluetooth keyboards and mice that all work fine. I have both Apple branded and non Apple branded keyboards, mice, trackpads that all work but the built-in keyboard and trackpad will not work.

Please help