My property is upside down, and co-signer owes child support. Will they place a lien against him?

I purchased a house with my brother in Nevada; he is the co-signer for a property which he does not live in (I live in the property), nor has he ever paid a mortgage payment.

After the house was purchased, he ended up having a child, in which he is going to have to start paying child support. If he does not pay the child support, will they place a lien against the property even if it is upside down?

In theory if they forced a sale, there would not be any equity to pay for any back child support, or am I completely off?

Also would they more likely garnish his wages for not paying before going after a house?