It's a tricky situation. You don't want to alienate your friend, but you also don't want to put up with the chaos her kids cause. Sounds like you need to have a face to face talk to her and explain the issue. Though, you'll have to prepare for possibility that you will lose a friend if she is too sensitive.
Don't cry, don't regret and don't blame
Weak find the whip, willing find freedom
Towards the sun, carry your name
In warm hands you are given
Ask the wind for the way
Uncertainty's gone, your path will unravel
Accept all as it is and do not blame
God or the Devil
~Born to Live - Mavrik~