90 chevy 1500

My boyfriend has a 1990 chevy
1500,  a few months back he
decided to give the inside a new
look along with new speakers ,
radio, amplifier, new colorful LED
lights,  the works. Ever since that
day , he has had to replace the
starter,  alternator , the battery ( 3x),  
in addition to disconnecting all the
additions to the interior, he worked
so hard on .  This situation has now
turned into a complete nightmare. ,  
the battery must be charged after
every use,  the headlights cause the
battery to die quickly. Which now
limits our ablity to travel at night .
No further than 1/2 - 1 mile,  and
the battery is dead . As we
approach the 1 mile radius. The
headlights are dimming, if the
wipers are needed , the distance
just got shorter.  Here's a few extras
that might help solve this problem.
The inside dome light only comes
on when the passenger door opens.
The driver side back running light
was the only light on one evening
as he drove with the lights off. It
seems to run good during the day,
for the most part .  I'm pretty sure
it's an electrical issue.  I've read
quite alot now hoping to get the
solution,  so I can be queen !!! LOL
.... please help.