Yes why isn't she telling muchael!?
(And I may have missed a bit has he just come back onto the scene for her to raise the issue - or has he worked either her for all this time?)
But yes it was frustrating she didn't tell him .and the longer it goes on the longer he'll be wondering why didn't you tell me. And I'd be pretty pissed off as the daughter merging in with the family like that when all along your mum could have mentioned you're related!!