...while grandma is healing. Funny thing is until grandma heals their younger roles are reversed: Grandma is effectively the baby. She needs someone to cook for her, clean after voiding, get her out of bed and going to another room and getting her dressed. Grandma is an Infant/Tottler until her leg heals enough so the doctor will change the cast and let hed use the leg. Mom is now the mother caring for her mom. Is grandma your mother's mom or your father's? Either way it's fantastic your mom's a retired nurse. She'll know what to look for if (God forbid it) trouble occurs.
My mother had knee replacement surgery at 78 years of age. When she was released we brother and I were lectured by doctor, her and nurse (was handling release) and the home healt care nurse that came out three times a week regarding the same subject: leg injury equals leg surgery and here's anothed booklet of what you need to do/watch out for. She came through it fine and was walking, driving and working in her flower beds.
Your grandma will heal and have no problems. She is in our thoughts and prayers for a full recovery.