When you elevate men to a position of authority with little or no training in how to handle the responsibilities, this is what you get. A man who probably knows what the right thing to do is, but thinks that throwing someone out of his dead grandmother's home is the 'acceptable' option that will get him the least amount of blowback if it becomes a scandal. And the worst part? The part where the sisters are taking opposite sides on this, due to the shunning policy. This has the potential to create a rift and leave many different scars, that will last a long time.
In short, bad policy and poor/nonexistent training = horrible situations like this.