@Kiekoes one thing is getting permission, and another is getting supervision, Parasyte has a bunch of compilations and spinoffs, which he gave permission to make, but didn't supervise, and this can be just another one.
If he is only credited once and is credited only as the creator of the original story, and not as a coauthor, writer, supervisor, consultant, then speculating about him being more involved when he already has to deal with History is just wishful optimism. Your answer didn't really tells me much, other than his involvement may be minimal.