Can BY Draconis variable stars sustain any form of complex life? I wanted to ask this, because while I was working on two fictional planets back on the Worldbuilding SE, one of them being habitable, which orbit the 61 Cygni A star of the 61 Cygni binary star system, I realised something: 61 Cygni A is a BY Draconis variable star. 

Here is the Wikipedia article link for more information. 

My problem is: can a BY Draconis variable K-class star like 61 Cygni A permit the development of complex life, unlike its partner, 61 Cygni B, is a flare star that can barely get life past the primordial stage, if any planets are there? Or does it have some problems in that regard? If so, what are those problems that a habitable world in that star system could have, and other star systems of the BY Draconis variable star category?
Life could easily form underground, where flares don't reach.  Never underestimate the power of 10^(googol) possible locations in the universe for living things to come into being.   No reason to limit to organic, or CO2 / O2 connected, or photon-dependent, life forms.