Is there anyway to either fork a process and force its output to /dev/null or simply make the parent ignore the child and continue?

You can literally accomplish this task by redirecting your STDOUT and STDERR to /dev/null using open in the child after your fork:

open STDOUT, '>', '/dev/null' or die "Redirect failed: $!";
open STDERR, '>', '/dev/null' or die "Redirect failed: $!";
[download]

You'd probably combine this in an instruction to not bother waiting to reap the child (see perlipc):

$SIG{CHLD} = "IGNORE";
[download]

However, you are treating a symptom here.As eyepopslikeamosquito says, this sounds like an XY Problem. I suspect your dissection of the system is incorrect, and what's actually happening is your child is hanging on STDIN that's not coming. Post code so we can actually diagnose this and fix it.