Bennie
Did your sister had her eyes examined recently? She could have tearducks plugged with mucus caused by protein deposits. It is a small procedure to unplugged them if she doesn't wait too long. A needle is inserted in the tearduck and injected with a saline solution which may do the job. Also if she uses tear drops like murine for example might help her tremendously. Hope it works out for her. My best advice would be to see an optomologist as soon as possible.