Sure they can. They can even garnish your wages!
Government subsidized student loans are forever. They cannot be discharged, not even through bankruptcy! So in general – your student loan will follow you to your grave.
They can go after any asset that you have to enforce payments of these loans. They can certainly put a lien on your home, garnish your wages, offset tax refunds and more.
If you have problems keeping payments, it’s better to call them up and see if they have any programs that can help you, like deferment
There are limited cases where outstanding loans can be forgiven. These include serving in the military, agreeing to work in certain economically depressed areas etc. However any loan balance forgiven under one of these programs generally becomes taxable income for you in the year that the amount is forgiven.