How do I help my Grandma she has a drug problem?

My great grandma is 92 years old and has heart conditions and isn't in the best health. She has been smoking methamphetamine almost every day for the past 17 years. how can we as a family try to convince her to stop without sounding over bearing and upsetting her? she is killing herself with this stuff and it really hurts us to stand back and watch her destroy herself. otherwise, she is a sweet old woman. she likes to sew and make quilts. she always bakes the best cookies. she's a very talented, compionate old woman, but she has this drug problem. is it too late for her?