I have read your many articles regarding children obeying their parents. What is in Scripture for parents to obey or respect their children? For example, I have been married for 27 years and now my mother-in-law has moved in. She is 71 years old and in good health, but she just can’t be bothered to do anything for herself. She expects her only daughter to wait on her. She has a very comfortable home and is financially well off. Her two sons have very little or no time for her.
What is my responsibility according to Scripture? I can’t go much longer with her in our home all the time. She has been with us now for five years. I accept that I did say for better for worse, but her mother lived until she was 98. It’s frightening. My wife is in a very difficult position. She can’t tell her to go, and I accept that. If I tell her to go and she got sick or died, I know I will be blamed.
What is our Christian responsibility and what is her Christian obligation? A man should leave his father and mother and cling only unto to his wife, also in reverse, a wife will leave and cling unto her husband.
First, let me ask you to read over the article "Honor Your Father and Mother." It addresses many of your questions. But let me then give some further application.
Honoring your parents or your wife's parents means that you treat them respectfully. When they offer advice, you take the time to listen and consider what they have to offer. It doesn't imply that you must obey their every whim, but they do have the advantage of experience and you should gain what you can from their experience.
Honoring one's parents also means seeing to their needs when they become too old to care for themselves. "Honor widows who are really widows. ... But if anyone does not provide for his own, and especially for those of his household, he has denied the faith and is worse than an unbeliever. ... If any believing man or woman has widows, let them relieve them, and do not let the church be burdened, that it may relieve those who are really widows" (I Timothy 5:3, 8, 16). Your parents cared for you when you were small and helpless. Even as you grew to be able to provide for yourself, your parents frequently stepped in to ease your burdens. Now, when they have grown old and feeble, it is your turn to return the favor. Honor them by making sure they are comfortable in their declining years.
It doesn't mean that you must have them living in your home unless you feel this is the best way to fulfill your obligations. You could put her up in an apartment nearby or, if necessary, an assisted living facility where you can regularly check that she is doing well.
In summary, treat your mother-in-law with respect and dignity. See that she is safe and secure. In her declining years make sure she doesn't fall prey to hustlers and scams. Call or visit her so she doesn't feel alone in the world. In other words, care for as you hope to be cared for in your declining years.