Should I intervene?

My good friend has recently (last 3 days) told me they have recently "within a month"? tried/started co*aine. And has been doing a "line" every two hours when they do it. And finishes an 🎱 in 3 or 4 days? Should I say something or keep out of it? I personally haven't noticed major changes in mood, Maybe more talkative.? I can say I know them well enough they loosens their self control when they think they can handle something responsibly. Etc. 🌲🚬 and 🍸.. I dont have any experience or know anyone that does? Would appreciate any real information and or insights! DM me if you dont wanna answer here. Thanks all for your time and consideration!