Welcome back:
I have to be honest, I'm confused. If the battery is dead, nothing should work. Here is what I want you to check. If the radio stops working, I first want to know where they got the power supply from. If it is direct to the battery, you may just have a bad connection, loose connection, the battery terminal is corroded or loose... Start there. Make sure the battery terminals are clean and tight.
It almost sounds like you lose power and then the battery is rendered dead due to corrosion or a loose connection. When you put the jumper cables on it to restart it, the connection is remade. Take a look through this link and try what it discusses.
https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked
Do this and let me know if it helps and what you find.
Joe
Wednesday, January 30th, 2019 AT 8:29 AM