So do something - like visit the love interest - that differentiates between these cases.
I know someone in a similar situation. She's been abroad to see her "love" in Egypt regularly, and he's very attentive when she's there.
Of course they're planning to get married.
Of course it's love. What else would it be?
Works on guys too. I know someone else who has given rather a lot of money to an East European woman. I don't think they'll ever meet, because most East European women in these scams are actually criminal gangs. But we'll see.
Also, it's worth considering that these scams are marketing funnels designed to select the most gullible people and filter out everyone else. So the victims are self-selecting, because the scams are designed to find people with their particular psychological weaknesses.
So you need a much better differential when you sarcastically say "of course it's love".
In the country where I was born, in my personal opinion (so this is not a neutral comment) startups are considered scams. Actually a few people elsewhere have expressed similar opinions. So, when you and an "online friend" get together and spend your own time and money, they consider it a scam. Like, if you are working with/for someone, they should be paying you! No concept of equity etc.
Now as we know, many stqrtups coasted by on "binders full of credit cards", were colossal risks. Adults have the right to do that.
Let's say someone tried to "get through to me" that there is NO SUCH THING AS SUCCESSFULLY RAISING MONEY OR A SUCCESSFUL EXIT. The problem is, they're wrong. There is such a thing.
So when you look at your mother's case - she disagrees with you. You are saying "this man is just lying to her" but she says, "no, no".
Well, ask her: does he talk about meeting her? Does he make plans to meet her? (I hope so.)
Have her plan a surprise trip to see him. It doesn't take much money to fly anywhere in the world.
If he is a scammer he will not want to see her under any circumstances. That will tell her all she needs to know.
What I mean is that you have to make her do something that is a differential between the two possibilities.