No, the original Pi B can play 1080p video just fine. The video is not decoded by the CPU. H264 and older codecs play just fine. It cannot handle h265 videos as it doesn’t have a hardware decoder for those. Kodi works just fine in fact. The interface is a little bit slow, but actual video playback is fine.
Last time I checked, homebrew on Linux only included cli apps. GUI apps are only available on mac. So you couldn’t use it to install a browser anyway.