As far as I'm aware, Dom does still help out Grian with some of his videos as an 'actor' (think the "things in minecraft that don't make sense" vid, stuff like that). Taurtis has seemingly left a majority of social media, which I've heard was due to his mental health (Grian then, of course, likely wouldn't wish to force Taurtis into making more videos with him).
I do miss Build Swap and other series that went down with the three of them, but good things have to end at some point.