Story of Burned Letter

Does anyone have documentation or knowledge of a story that after James Wanlass (1825 – 1895), emigrated from Scotland to America and became established in Utah, he received a letter from relatives back in Scotland? He allegedly was so angry that he tossed the letter into the fireplace, exclaiming that “They didn’t need me then, so they don’t need me now!” 

 I first heard this story from distant relatives. Then last year, my aunt (Audrey Bush), mentioned the story before she died. I wonder who else knows the story and what it may mean. James knew he had been abandoned by his family. He didn't know who his parents were, but there have been rumors that he had a sister. Did he know about any siblings? Was he resentful that they might be contacting him after all those years of abandonment? Does anyone have information about siblings for James Wanlass?