I know it is recommended that they be housed individually but I do know a guy that keeps 6 good sized females in a 55 gallon tank with no problems. He does move them to feed. If it is a temporary situation I would let them stay together. They are both females anyway so you don't have to worry about them breeding young.
6 snakes in a 55gallon tank is animal cruelty. If there arent any problems then that shows his complete lack of knowledge for bps. I assure there are problems and there will be more for him in the future...