I wouldn't stop being her friend, I think she needs someone like you around to help her even though sometimes it may be hard. You should talk to her about the boyfriend and see what happened. Maybe something happened in the relationship and she is really hurt by it. It may not be a good thing for her to have a boyfriend but you should let her know you are there for her and all you want to do is see her happy and becoming a good Muslim.

I would let her know how you feel as her friend. Tell her how it makes you feel to see her going down the path she is going down. Let her know that no one is perfect and we all have our faults, but we should learn from our mistakes and choose to live better life’s.

I hope this helps sister. Stay strong and pray for her. Allah Alum. Allah will InshAllah guide her to the straight way.

Stay strong sister!
I wish you all the best!

Salaams!!