A proud mother's message to her son

Wilson has received a letter from his mum, Mrs Vermilingua. She says that what with Boo having so many stepfathers and half-brothers and -sisters, (including several that he's not met yet and a few more about to be born any day) she has rather lost track of birthday dates and has no idea of the date of his birthday. 

However, she assured him that she is very proud of him and all his achievements.