In my team, we are only two : Jack and me (Franz left the company a few weeks ago). Jack and me are both technical people, and I am younger than Jack (25 years old, he is 35).
We both work from home, and see each other and the other teams every month. Often, he will come up with claims that he thinks are true, but he will never have more arguments than : "this is a convention". Most of the conventions he's talking about are not verifiable, and are totally strange to me. Whenever I ask whether he could explain why exactly it would be good to use that convention, he usually doesn't come up with more arguments than the convention argument.
The other teams seem to agree with me that he is not always right with his conventions, but they don't seem to want to take position against him. Since I'm younger than my coworker and we are only two in my team, I don't feel good to impose my decisions. It was much easier at the time when Franz was still there, because he liked to know the reasons behind things.
Also, very often, he participates in conversations with other teams and gives propositions which do not make any sense (because he doesn't understand/know the whole context of things).
Our mother language is not English, and we use some communication channels where we have to speak in english. In those channels, Jack is even less clear and it makes communication very difficult sometimes.
I don't think that the behavior of Jack comes from bad intent, but it makes my work less interesting than before, since I always have to argue with him that his conventions are sometimes wrong, and a lot of decisions are left pending since we are only two to decide and we can't find an agreement.
I really enjoy my work here (the subjects are very interesting), so I don't feel about quitting yet.
Is this something I can talk to my manager, and how could I explain him the situation ?