Is it true you're not supposed to touch someone with a suspected drug overdose?

I'm not a paramedic, but I have a question if it's okay for me to ask it here.

Tonight on my walk, I found a person lying on the grass, breathing rapidly, moving their limbs/jerking, glossy eyes. I immediately called 911 and they came to help quickly. However, the other passerby told me I shouldn't touch this person because "if it's fentanyl and it gets on you - you're dead".

Was he exaggerating or is this a real issue? I did turn him and place my coat under his head because I was worried he would vomit and aspirate.