I don't think that 2 acres will support 2 horses no matter what she plants.
X2.
2 acres is not a enough pasture for 2 horses, its more like a pen. they will have to be fed year-round, no matter what. without it, they will eat down and kill out any kind of grass. if you put in some kind of grass AND feed enough year-round, the ground will help support them a little.
but i know what it's like trying to tell the mother in law something. mine is the same way. she has about 9 horses on 10 acres and just cant figure out why they dont do better.
