Write a thoughtful letter to my mother-in-law asking her to move out of our house and in to a retirement community.  Make sure to thank her for her help and be kind.  She has lived with us for 5 years and helped us when our kids were little.  We want her to move out in the next 6 months, and we will pay for her retirement home and care.
Dear,
It has been great living with you for the last 5 years.  When our kids were small, you helped care for them and made a big impact on their development.  We could not have raised them without your help.  Now that the kids are older, we want to make sure we are not slowing you down or keeping you from your retirement goals.  In fact, we would love to return the favor you did for us, by helping you find a retirement community that you can enjoy and prosper in.  We are happy to pay for all of the accommodations and ensure moving is as easy as possible.  We think it is best to make this change in the next 6 months, and we will do everything we can to help you navigate this important transition, for you and for us.
Love Always,