I'd drop him faster then I'd drop my many bad habits.
Basically, he probably playing you, heres why. Compared to selling petty amounts of narcotics, Planning/committing 1st degree murder is MUCH much more serious. Ergo, even if you confess selling narcotics in petty amounts, as part of a reason why someone is trying to kill you (if you can come up with decent evidence of the plot) the police here in Canada are unlikely to charge you on the CDSA offenses but are obliged to give you protection from the plot on your life... So he could always go the authorities if he was genuinely afraid for life and limb. (and even if they do follow up on the petty crimes, your 3 weeks in custody and 6 mos probation are worth not getting killed for)