I sometimes end in face-to-face conversations/debates with my (adult) brother over a variety of topics that he usually brings up himself. They're often the kind of topics I don't pay much attention to or care about that much (certain political things, religion etc.) but I don't mind talking about them since my brother is obviously interested. There are exceptions though, where I do have an interest and an opinion on the topic, yet the behavior I'm trying to describe is the same.
I've just noticed this weird trend where he brings up a topic for a debate verbally and talks about it for a bit to me, if I respond some way (ask a clarifying question, present a countering opinion etc.), rather than answer me himself he tends to reach for his phone to show some video/stream/whatever about it and asks me to watch it for answers instead. The videos he uses are different based on the subject, it isn't any one person's videos.
While I wouldn't mind him fact checking on more technical subjects, he'd rather the video personality to answer my question even if what I said is opinion-based and doesn't require high level knowledge on the topic at hand and I wish he'd just present his own thoughts about the subject instead.
Example
Me and my brother are talking about a subject my brother initiated. He hasn't mentioned that the topic is from a video he watched previously but since it's a regular occurrence, I already half-expect it is.
Brother: "...and if [Subject X] was like that, it would probably [Opinion Y]."
Me: "I guess... But what if it was [Opinion B] instead?"
Brother: "Hmmmm wait a second..." He then starts rummaging for his phone in search for the video his topic came from. He searches for a while and gives me the phone to watch some of the video. Usually the part he shows is much longer than is needed to answer and sometimes doesn't give a proper answer to my question anyway.
Me: "I mean I guess what he's talking about is true but I don't think it answered my question..."
My brother: He takes the phone and tries to scramble for a possible other video and usually gets frustrated and tells me to watch the entire thing (sometimes hours worth of material.)
I'm then left confused why he brought up this topic at all if he didn't want to discuss it himself. Maybe I shouldn't have posed questions to show interest at all?
Not only I have no interest in watching a 20 minute video about a topic I'm not all that interested in just to hear an answer to a single question, but I find him having to reach for answers about a topic he initiated weird. I also don't want to debate on an opinion not voiced by my brother since it usually turns into him trying to scramble to find if this internet personality has said something on that topic as well, giving me the impression that these aren't truly his (my brother's) opinions at all. I'm here to debate with the bro, not the video persona.
I've tried to ask him to try and sum up the answer to me himself but this seems to frustrate him. I'm not sure if he feels the need to rely on outside sources to explain his points because he hasn't truly familiarized himself with the topic or if he just isn't that fast/good at condensing info to others. Might be that I just need to bite the bullet and let him have his debates via proxy or just let him go at it with no input from me.
TL;DR; I'm not sure if this makes sense, but How to have a casual face-to-face debate on a random topic someone initiated when they never present their own arguments and just want to use streamers'/internet personalities' opinions on the topic instead and do this by just showing the video/audio/text in question, without trying to explain them to me themselves?