It sounds like a really difficult and emotional situation, and I completely understand your concerns. I think for most people, this kind of decision triggers a very strong gut reaction—either an immediate "no, never" or an immediate "yes." Unfortunately, if her initial reaction wasn’t a firm no, she’s probably already decided to do it and is just trying to justify it to herself and to you. At this point, it’s less about helping her make the decision and more about convincing her that she’s making the wrong one.
One of the most important things you can do is thoroughly investigate the person making this offer. It sounds incredibly shady, and there are a lot of predatory agents in that industry. If she is genuinely considering it, she needs to be fully aware of the risks—both in terms of exploitation and how this could impact her future.
I’d also strongly encourage her to watch interviews with former adult film stars who have spoken about the long-term consequences—both mental and physical. Many regret their involvement in the industry, and hearing their experiences firsthand might open her eyes to the reality of what she’s getting into.
Most importantly, she needs to truly understand that once these videos are out there, they are permanent. They will follow her for life, affecting her professional opportunities, personal relationships, and future family. It’s very unlikely that she will find a long-term partner who is ok being with someone that has this as part of her history, and that’s something she needs to seriously consider.