You have three choices:
1. You also become unreasonable and/or use inaccurate justification. This will surely make things worse for both of you.
2. You just ignore the person and become indifferent. Sure, this may be better than the above approach, but will still not solve the issue.
3. You make a concerted effort to understand the unreasonable behavior and inaccurate justification at a deeper level to see what the reason behind this behavior could be. This has the highest percentage of initiating a breakthrough process.
If you want a behavioral change in others, you must begin by changing the way you look at their behavior. Then, follow up with having a dialogue that’s rooted in their paradigm, repeating in your own words what you understand they are saying. This makes them feel validated and heard. This opens the door for you to share with them how you personally see things.
The final step is to make the problem ‘before you’, not ‘between you’. This way it is not ‘him against you’. It is to some extent mutually beneficial, without accepting unreasonable demands. This approach will yield the highest chance of achieving success.
If for some unforeseen reason this process does not work, then a stronger approach is validated.