You shouldn’t need another pic, just turn on HPWM, and leave it on.
then use that as one input to an AND gate, and your HSEROUT pin as the other,
then the AND gate output should be the modulated serial.

The IR receiver modules don’t go well with a constant carrier, at least in my experience,
and also your output from the IR receiver module might be inverted (relative to what you expect).
You might need a 7404 or similar at either the send or the receive end.