Hi, I'm not sure if this is the right place to post this (apologies if it is not or if anyone will be able to help with this but I'm trying to find a book for my fiance. It's one she read a long time and unfortunately can't remember many details...

Basically what I know is that it is set in the modern time, the main character is male that is aware that there are parallel universes. His mum (or possibly both parents) are dead, but he knows that she/they are alive in an alternate world. The boy refers to 'the other me' or 'the other mummy' or something similar.

Unfortunately that's about all she can remember. She doesn't think it was necessarily all about the alternate worlds, as there were things going on in his life in this world...

So, that's quite vague, I admit, but if there is any chance that anyone recognises it, please let me know!