personally if your kid is almost 18, i might turn a blind eye to them smoking weed if they are responsible and getting their stuff done, but honestly, if they are smoking resin, i might talk to them cause they are probably uneducated about drugs, and who knows if they are going to take something stupid... smoking resin isn't really something an educated user would do imo.
I smoked resin when i had nothing. It's nasty but better then nothing. But with legal weed theres no need really. Granted i live in Canada so we are lucky with this shit