I had to call cps on my friend who tried very hard

I hate that I had to make this decision because I fight with myself on whether or not it was the right one. My bestie who is literally my sister. I lived with her family for years. She wanted a baby but was struggling with infertility. She had 3 miscarriages in one year. She finally conceived her son who I consider my nephew. I guess her husband didn't want a baby as much as she did so he left her. She had him and he was so beautiful. He's 4 now and she still breast feeds, which is her choice. She always talks about how much he looks like his dad. O knew she was still in love with her husband very much. Last month she was texting me saying she was having weird feelings. I asked what she meant. She said "I'm developing sexual feelings towards my son." I called her to talk to her and she says he looks so much like his dad and she misses her husband and she's now developing these feelings towards her son. We talked for about an hour. I didn't want to call cps right away. I wanted to get her help. I though if I could get her help then we wouldn't need to. I told her to let me or her mother take care of him while she goes to get help. She declined and said she wouldn't do anything to him. Its just feelings. I keep going with my offer and she kept declining. She texted and called me about it. In the beginning she sounded guilty for feeling this way which is why I didn't call in the beginning because she knew it was wrong and I thought I could help her. Then she went from sounding guilty to sounding angry that she can't act on what she wants to do. Her texts were getting so disturbing that I had to call at that point. I thought I could help her, but she kept refusing and she was getting very disturbing and if I didn't call I was afraid she was gonna do something inappropriate to her son. He is fine. Hes with his grandmother, however that family is not happy with me and I've been thrown at of the family I've known for so long. Her sons grandmother isn't that upset with me. She's happy I told, but everyone else is pretty pissed off. Sometimes I go back and forth and say I did a bad thing because she would have hurt her son, but I couldn't leave that up to chance. Hopefully her son will stay loved and safe. I am not in her sons life out of respect for the family, but hopefully hes in a good situation.