Well, it's possible. But it really depends on what kind of manga it is and if your mom has an open mind to the genre. Some manga have universal appeal, while others might be more niche. If you find something that catches both of your interests, it could be a great bonding experience.
As of now, in the manga, the identity of Luffy's mom remains unknown. There have been many theories and speculations among fans, but no official confirmation.
As of the latest chapters, Big Mom did die. The circumstances surrounding her death were quite complex and tied to a series of intense battles and plot developments.
Definitely not. Loving your mom in the context of hentai manga is completely unacceptable. It's not only morally wrong but also violates social norms and can cause harm to individuals and society.