Answer:
I say this because I want to see your friend in Heaven, not because I want to judge her. The Bible says (talking about the rapture)…
1 Thessalonians 5:2-6 For yourselves know perfectly that the day of the Lord so cometh as a thief in the night. For when they shall say, Peace and safety; then sudden destruction cometh upon them, as travail upon a woman with child; and they shall not escape. But ye, brethren, are not in darkness, that that day should overtake you as a thief. Ye are all the children of light, and the children of the day: we are not of the night, nor of darkness. Therefore let us not sleep, as do others; but let us watch and be sober.
Please, use tough love or whatever it takes to get her the help that will lead to eternal life and everlasting happiness. I will be praying for you and for her. You are a good sister and I commend you.
Also, know that God is on your side and He will work His part as well…2 Peter 3:9 The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance.