have you ever heard of " easy outs" . They are reverse cut bits that are similar to a drill bit but work in reverse. they usually come in a kit. You tap in the one that fits into the bleeder hole ,then use a wrench, or the tool it comes with, to turn the bit to the left and hopefully remove the broken bleeder.
I use a heat gun , not a torch, to heat up the area and liquid wrench also. take your time. It may take multiple heat/ cooling ,liquid wrench applications to loosen the bleeder.....hope this helps and works .......