Ive got a question about anaesthethics?

my mother is 86 and is urgent need of an operation for a broken thigh bone. for the last 7 weeks theyve had her leg in traction and its not healing well at all now they have told us they have got to operate cos they cant leave her like she is. shes got a very weak heart and her kidneys are failing the hospital have said they are going to talk to a professor of anaesthetics to see the best way to go about this operation, but how can they operate with anaesthetic cos they couldnt do it 7 weeks ago cos of mums heart. does anyway have an answer for me im worried about my mum.could there really be an anaesthetic suitable for my mums operation.