Hi Sam88, thanks for writing. So funny that your post came today, as I posted a new blog titled "I can't reach you" about 5 different generations of employees in the workplace. Here is the link, communication is a major issue … https://www.thecorporaterookie.com/business/i-cant-reach-you-timeless-skills-for-a-5-gen-workplace/
It sounds like you are frustrated by dealing with a younger boss. There is a good chance that he could be threatened by you or just overwhelmed in the role. Either way let's give him the benefit of doubt and point the problem to you.
The fact that you say "I can't get him to listen" has a very negative connotation and is hard for me to believe. The first thing you should do is identify why you are making him defensive. Most people don't just start-off that way. Have you done something in the past to upset him or shorten his fuse? Could you have possibly put him down or countered what he said in meetings?
The second thing to do is identify who your boss does listen to and determine what this other person is doing differently. Perhaps, he or she presents data to your boss in a more replete or compelling way. Maybe the tone or setting is different?
There has got to be a right way to communicate with this person and you need to find it. If your ideas could really save the company money then let the data do the talking. No boss in the world would frown on an great opportunity to save company dollars. Present the numbers and facts to support every detail as to why your approach is the right one. A very logical and systematic offense demands a similar defense.
Catch your boss when he is in a good mood. Perhaps that's early in the day or just after he announced something positive about the company. Ask for a quick minute alone and let him know how you feel. In a positive manner, ask him if there is anything you could be doing better in the way you communicate to him.
Never lose sight of the fact that your boss is the one paying to keep you on his team and not vice versa. Every employee is dispensable, so do whatever it takes to stay in good light. Learning how to manage up to a younger boss takes patience and effort on your part. Good luck!