Older player hijacks the campaign. what do I do
This all started when one of my friends invited me to a campaign of his, I was kinda thirsty for a campaign as I had mainly played in one shots till then, so when he told me a mutual friend we'll call D and one other friend of his were in it I was excited to meet him. First session comes around and an important note, I was 16 at the time and D was 18, DM was in his late 20s so I though I would find out this friend, lets call him "Jay", to be about the same age, 20s maybe early 30s. Well to my surprise I find a 50 something year old fellow who's been playing D&D since 3.5 edition.
The first session goes well, I wont get too deep into the premise of the campaign as that isn't very relevant to the story, but its an Isekai type story where the PC's are from other worlds entirely, finding themselves in this foreign world. But one thing I did notice was that Jay was constantly debating the DM on rules that were from 3.5, when we were clearly playing 5e. I didn't think much of it, but it got slightly annoying. The DM told him it was 5e but he just kept doing it!
Second session rolls around and I really start to see what kinda character Jay is playing. A wizard with the overall goal of learning all kinds of spells out there. Turns out he can use spells from other editions and even other games (eg. pathfinder) at first I was confused as to why he could do that, but later on it was explained to me (by the DM) that it was an ability he had, since the isekaied characters could bring abilities from their own worlds, that was his. Another thing that came off as a red flag to me was that he said that theatre of the mind was for "poor people" and that D&D was meant to be played with minis. Either way, he was very critical of other players, constantly telling us how to play our own characters an example is that he questioned why I don't use more spells other than eldritch blast when I was a Warlock, a class notorious for having little to no spell slots. You could write it off as him trying to give advice but it comes off more condescending than helpful.
Another quarrel I had with this player is that he's been wining for almost the entire campaign that we should switch from milestone to XP, and the DM said that he's seriously considering switching just to shut him up instead of putting it to a party vote, which I feel just shows the DM's bias towards the situation.
One last thing I noticed is that he doesn't use any devices, like at all! and he complains that me and D use D&D beyond instead of paper. He explains that "thats basically a video game were playing a tabletop game!" but when we do play he wants to do XP and constantly reminds us to fill up water skins and rations, which I feel is the most videogame like ascpect of D&D. I find that quite hypocritical.
My real question is, what should I do, I cant ask the DM to kick this player because he's a friend of his, I feel like the DM is giving Jay some special attention and feel powerless to do anything, your thoughts.