Engine shut off will not start

My grandfather gave me his truck and after driving it a few times, I noticed the AC/heater would not blow through the front vents, only the top windshield vents. Also noticed gauge lights would work intermittently.
When I started the truck to leave for work this morning, I noticed all of the gauges and lights on dash cluster were not working, as if the car was off. After work, I stopped by the gas station just to make sure I had enough gas to get home since the gauge was still not working and I could not tell how much gas I already had. A few miles from home, the truck started jerking then completely shut off as if it had run out of gas. AAA towed the truck to my house and sent a service car out to check my battery and alternator. Battery read low at 7.7, and when he took cable off to check alternator, the truck just shut off. I’d rather fix the problem at home, if possible. I’m just not too sure where to start. Could blown fuses be the cause? Should I just replace the alternator?

Please advise!

Thanks, Monyque