What Are the Long Term Effects on Salvia?

my boyfriend wants to smoke salvia, i don’t want him to i’m scared and he knows how sensitive i feel on drugs… my dad just got out of rehab and he was an alcoholic and drug addict … he wanted to smoke weed and smoked a couple times then stopped after i told him how i felt he says he just wants to try salvia that’s all … should i tell him how i feel or just let him do it… i don’t know what to do..