The best way I know of is acknowledging that his perspective is in no way less valid than mine. And to keep in mind that such a decision is always far from being objective, anyway.
When you discuss this topic, always be clear that the goal is not to use library X. The goal is to solve a problem. You first need to agree on what the problem is. Then you need to agree on what the criteria are for solving the problem. Then
you should explore options: what different solutions are available? Be creative. Only then you can make a good decision.
Also keep in mind that a decision doesn't have to be final. Often the best decision you can make is in the form of a timeboxed experiment.
It also doesn't need to be in favor of exactly one solution. Often it makes sense to try several solutions in parallel for a time, to be better able to evaluate them. Make sure that it's not just "everyone evaluates his prefered solution".
Hope this helps.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus