You should remove all the heave stuff from upstair room especialy bookcase or panio. and then apply some woodglue in the gap(indoor usage) lift up the beam useing 6x2 wood (diagnal first and then hammer to vertically). it should be lift up 10mm and close the break gap and wait for two days. then you need two 8"x2" wood both side bolted by 3/8" throught bolts. or 1mmX16"x16" steel metal sheet with lot of holes( sold in HD) wrap around the existing broken piece and screwed with mornal wood screw. you can remove the 2x6" wood support.
if don't like to doing any thing, you can just remove some heave stuff in upstair room.
if don't like to doing any thing, you can just remove some heave stuff in upstair room.