iPhone won't turn on

My brothers iPhone died when he updated it to I think iOS 13.6 (he doesn't remember and I wasn't there at the time). To be more specific when he updated it the phone turned off like normal then never turned back on. We have charged it for a day then tried to do a hard reset, nothing, I put it on a wireless charger and charger says it's working but nothing happens, I've even plugged it in to my computer which caused it to make a sound but nothing came up. When I called apple support for help I had to wait for three hours but they never answered. Is there anything else I should do or do I a very expensive paperweight?