Looks like this will never be an issue again :'(
According to an article on Kotaku, Halo 5 Development Director Frank O'Connor mentioned on a NeoGAF forum that split screen play will not be in the upcoming game. He addresses the lack of local multiplayer as a drawback to keeping the game running at 60 frames per second.
While many have taken this news to be a drastic drawback for the title, 343 Industries seems to be trying to shift the conversation to what good will be coming from the reallocation of resources, such the 15 free DLC map packs set to release within less than a year of the title's release.
"Hey buddy, i'm not happy about it either. Doesn't mean you have to put a gun to my face!"
As a gamer who grew up with local multiplayer and had his fondest memories of gaming with his friends beside him, this is disheartening. I feel that those who are unhappy are justified, as Halo has always been the hallmark for quality local multiplayer and system-link shooters.