[US] Celebrity romance scam currently happening with my mom's friend

Hi all, I just need some advice on how to help my mother's friend.
She is recently widowed and in her 60s. She believes that Riley Green, this 36 year old country music star, is in love with her. This began about 2 months ago when she matched with some older guy from LA who is apparently a famous and wealthy songwriter. He told his client "Riley Green" about this woman and apparently he fell in love with her. She now texts him day and night and sends him pictures of herself. He wants to get married to her in December and has sent her rings to try on to her home address as well as a pizza from Dominos (the 9.99 Coke deal). She also had to purchase backstage tickets or something and spent $1500 at wal-mart maybe through gift cards? I don't know and the cashier asked her if she was getting scammed and she denied this allegation clearly.

The details of everything is a little spotty because "Riley Green" told her not to tell anyone as he was busy with tour and wanted to wait to announce their engagement. The only person she told is my mother because mom has a pool and her friend wanted mom to take pictures of her in a bathing suit next to it to send. My mom has tried to ask her - well why wont you talk on the phone or facetime or meet in person and she just said he's too busy with the tour right now. And also that she knows they'll be married because why would he want to talk about their financial future if he wasn't serious. Oh boy. I believe the scammer knows she is closing on her and her late husband's house at the end of the month and is trying to get her bank information - i think that's what her address helps with as well with the pizza?

Alas, how can I help this woman? how can we stop this from happening? She doesn't want to believe its a scam... I just.. It is so sad because we are watching the process of her about to lose everything...