Russian Visa EMERGENCY NEED ANSWERS ASAP?

This is the deal: My grandmother's best friend died unexpectedly in Russia. They were as close as sisters and their families are inseparable. My grandmother, being Russian, but having an expired Russian Travel Visa (Because her pport and citizenship was revoked when she fled to Austria before the collapse of the soviet union) needs to fly to the funeral on Nov 30 because her friend's family needs her and theyre falling apart. Any tips on what she should do in this case? If she flys there, will she be sent back or detained for not having a visa? Is there any way (her birth certificate or her friends death certificate) theyll let her through? She has an American Pport and is a citizen of the US. Help?