Share of royalties? Maybe, but I don't think so. Or maybe so, maybe she's helping them out, many artists do that.
I believe most parents would be ashamed if their kids, especially daughters, would be promiscuous, so let alone escorting, and especially in her own town or region, and possibly fucking guys their parents know, wow... Maybe her parents are in the minority that really don't care. Or maybe they know but still don't agree, I don't think the article says any of that, maybe the book will... If I had kids, I sure wouldn't be proud of my daughters doing this for a living or anything related to sex work and porn, and I sure wouldn't encourage them either.
She didn't have to show her face on the cover nor did she have to use her real name to publish the book (if it really is her real name). She could have went anonymous, but she didn't, I wonder why... Are books sold more expensive when you show your face or use your real name, kinda like webcam and porn videos? Maybe she wanted to take a stand as a former proud sex worker who wasn't and isn't ashamed to have worked in that field? That might be it, as for me, girls that are brave enough to show their faces are more likely to feel liberated, accepted, be proud of who they are and what they do, and at the same time, make those feminists and anti-prostitution people mad, unlike those that hide it for privacy and fear of judgement and criticism.
I believe very few sex workers will be honest with their significant others about their past or current work. If a retired escort prefers not to disclose her past job, it's not that big of a deal if she always hid her face, but to lie about her current work, that is cheating, and of course, this type of work comes with obvious health risks, so it's one thing to accept these risks for yourself, but to secretly put the other one at risk, that is very wrong and selfish... I never lied about my work, I don't want the repercussions and consequences of lying about something this serious. It's all about respect for the other person.