Married to a woman who happened to be the first born in a family of 5females and 1male, one of the female is living with us because she gained admission to an institution in the same city we live, God has blessed us with a kid and also expecting another one, though my woman hasn't secured an employment since we got married,. Her sister traveled home for one of her sister's graduation ceremony (secondary school) while coming back, she came with their last born without my knowledge, though my wife claim she knew nothing about it also....even their parents didn't informed or call me till now about the girl, please can I just keep quiet or what should I do ?
Note: They have always been a good inlaw to me but we all know what this country is saying now. Advice please !!!

Well i will advice you to chat up privately with your wife about the recent developings at home. make her understand your point without her having a feeling that you are trying to chase her sibling away. She will understand. but op mind you, she is the first born, so be expecting more of her siblings at your house. but atleast she should tell you when any of her siblings wants to visit and if you have any objecting, dont fail to point out reasons for your objection.

You go dey marry first born. U nor know how their matter be. DAT one mean say extra responsibility. U b uncle for her younger ones eyes so u knw say u GATS spend money for their head