iPhone 6s Plus, iOS 11.2.1, reboots every 5 mins, not charging past 3%

Hi there iFixers, I need your help, my father's iPhone 6s Plus won't charge past 3% since today, and keeps rebooting, we all use the cables that came with the phones so everything is MFI, I already put the iPhone in DFU mode and updated the iOS to the latest version today, and the problem persists, I seriously hope this is a software problem and that it won't need to change the logic board, any suggestions? I've already tried most if not all of the steps I was prompted by google search.

Thanks