What do you do when your kid is being "stupid" ?

I've watched a few episodes of 90 Day Fiance and they have this girl on there who is 20 (with a 2 year old) who is engaged to some guy from Morocco.

She has a minimum wage job and sends the guy money.

Her family opposes the engagement. She asked her mother and step father to cosign the guy's visa (which would make them financially responsible for him for 10 years) and they refused.

She then told her father/step-mother that if the guy couldnt come to the US then she would go live there with their granddaughter.
So they agreed to co-sign the visa.

I think the father agreed mainly because they dont want their granddaughter to be in a foreign country. They want her nearby so they can help raise her (cuz the mom has no clue)

What are you supposed to do when your kid is a fucking idiot?
You can't just say "do whatever you want, I dont care" - because she is your kid, and you obviously want to spare them from their own stupidity.
But you can't just keep giving in.

Look at my wife and blame her.

I tell him that is directly affiliated with your nappy hair.

Fuck him to establish dominance.

Wait.........what?

You can’t give in just because they’re your kid ...let them learn a lesson in life ....unless it’s critical , then step in and help 

buy her a van to live in and say goodbye forever

Late term abortion for the daughter, raise the grandkid as your own

Time to be a big girl so bye bye!