I didnīt see this as Magneto caring more for Rogue,he just has spend more time with her than with his children so she is more clear in his memory, also the children are kind of hidden for "spoilers" I guess
but all of them are dear to him and thatīs why they are on the boat but they also represent his own sense of lack of family and isolation from bassically everybody.
At this point Wanda and Pietro are on Operation Galactic Storm, off world with other avengers acording to Beau but before that they were not close to Magneto, they discovered their relationship when Magneto was looking for Magda but they pretty much stayed out of Magnetoīs bussines and he from theirs, except for that time Pietro was captured by the phalanx and Magneto helped to rescue him along with Forge and Beast.We donīt know how is his relationship with Lorna but itīs probable itīs similar.
So he has adult children who grew up without him, that donīt need him now and donīt expect to be family to him, his first wife Magda ran away from him and keep his children hidden from him, his parents and sister were killed off and only he survived, his first child died in a fire and while he cares for Rogue he knows she doensīt care for him as he does for her, everything that happened on Genosha, kidnapping, torture and Charlesīs attack was destroying his psyche.
I found this very interesting, for the first time Magneto was talking about his trauma in relation to his lack of family, his lack of bonds to humanity in general, all he had were ghosts and now he was losing them as well given he could not remember his parents faces, he is still grieving the families he lost and he sees the X-men as Charles family, he took on the mantle of leader of the X-men as a favor for charles, not because he expected to be accepted by the X-men as part of their own, not his own, it was until Charles let him known that if he truly wanted to he could be part of their family too and this healed him enough to remember his name and what he had to do to save his new found family and the world.
Loved this moment and how the theme of found family applies to Magneto as well. This theme has been tackled in comics as well but not as directly as this chapter did and it was really well done by the writers, because itīs precisely this lack of bonds, this sense of isolation coupled with survivors guilt the things that had keep Magneto in the past from healing from his past trauma.