You don't write anything about iPad's origin, about its last known moments. This is very important information that you need to take to take any action. My guess is that the tablet shut down one day and was under repair somewhere. I think he is just as raped as anyone else for now, with similar experiences.
<br> In a few cases, these were damaged pins in the charging port (in which case electronic confirmation is required). In others, in most cases, if someone opened the iPad, most likely, when trying to disconnect the battery, he broke the power contacts. If you are into microelectronics, you have to remove the board and check the connections. If you cannot solder and do not have the necessary technical background, find a good repair shop - really good one, you have to confirm its references - otherwise your tablet will never turn on again (due to lack of technical knowledge - most of them are still learning on YT).