What do you suggest if my sister has recently had the index and middle fingers of her left hand accidently cut off (but shes right handed) is that a disability?

An impairment...: ...technically. Loss of anatomy or function is considered a disability when one loses the ability to perform an activity as a result of an impairment. Many people have fingers amputated and are still able to function at or near 100%. Granted her injury sounds significant though and followup with an amputee specialist could help with all aspects of helping her return to prior functional level.