Keep them apart. The older dog deserves some peace and quiet, especially at that age.

Must be horrible to be leapt on, harassed and mauled by a youngester. The old one may be feeling sore or painful.

When they are together, place your younger one on a leadd so that you can prevent her from being a pain.

__________________

I am just a worthless liar.
I am just an imbecile.
I will only complicate you.
Trust in me and fall as well.
I will find a center in you.
I will chew it up and leave,
I will work to elevate you
just enough to bring you down