Sometimes, all you are expected to do is listen. You may be misled into thinking that your friend needs help, when in reality, all they need is for you to give ear to their ranting. They’re not looking for a solution but a way to remove that suppressed energy.
Forgive their rants and be the friend you must be. Listen and let go. You may not be rewarded for it right then but karma has a way of making this fruitful for you.