So with ALL of my bloomers being out of commission for one reason or another and my complete inability to sleep recently I did repairs. The torn off button and ripped seam were easy enough fixes but here's a way to fix elastic in a casing should it rip out of one end.
What you'll need:
Sewing materials (ie machine and thread)
Then redo the casing seam (in my case a top stitching) and voila! Fixed bloomers!