Hyundai sonata 2011 died while driving then break pedal stiff and won't start

I was driving on the highway and all of a sudden
my car got weak and wouldn't accelerate so I
pulled over and it wouldn't restart. The break
pedals were stiff and when I press the start button
I barely hear anything to sometimes making
sounds but won't start. All the lights and radio
working and they checked the batteries and said
they are fine. Got it towed to my house because it
was during a snow storm and few days later the
battery is completely dead. FYI I didn't get a oil
change in awhile. What do you think the problem
could be? Any tips would help. Hope my motor is
not locked!