I'm having problems with 2007 silverado ext cab, battery drains dead over a few hrs, cant even jump start, lights and all guages work while jumping, you turn switch nothing, stuck relay in alternator?

2007silverado, battery appears to be dead, tried charging, jump starting off a 60 amp
jumper/starter, turn the key, all lights go out,gauges die, nothing else happens, starter
doesnt even try to kick in. A friend of mine has a Z71 he bought off a guy it was doing
same thing and he was told it was a relay inside the alternator that was stuck open is
the cause, well at the time the guy didnt have 300.00 for new alternator , he installed a
toggle switch that some how intervenes with that relay and was a temp fix, all I know is
truck ran fine earlier that week no problems or indcations there was a problem with
anything starter, battery, or anything else, just happened overnight, not sure what to do
with it, any suggestions, you can email me at davidcarroll6423@gmail.com, thanks for
any advice...