Hey, back in the late 90s I bought a laptop from a reputable seller and had literally no idea who the manufacturer was. Was a pretty good laptop for the era too. The badge on the back of the monitor said "Notebook".
I had to put the product ID code on the bottom into an online search engine - possibly very early Google - to find out it was made by Taiwanese company called Kapok.
Kind of wish I still had it, but I donated it to a good cause years ago.
Nobody would ask for the brand in reality. For 99% of computer issues it's going to be something specific to the used software or Windows, and if the hardware turned out to be relevant in any way, you'd ask for the model because the brand itself is useless for most issues.
The brand can be a great identifier. If the response is "Apple", I can't help you. If the response is "HP" or "Dell" or "Walmart", I know the issue is likely because of proprietary garbage that's locked down "for the safety of the user".
When speaking to the computer illiterate, the brand question will usually be answered with either "Apple" or "Windows". You gotta get that answer out of the way so you don't waste 15 minutes trying to get someone to right-click something only to find out they only have 1 mouse button.
Of course you ask the brand. With the less tech savvy, you need to be clear and specific in your language. If you ask "is it a macbook?" you'll get confusion as reply. People understand brands though. Even asking if it's Windows might be confusing, because Windows is all they know.