From the result of certain beliefs bragging is a bad thing but not every bragging is bad. Sometimes will be a useful and inspirational thing to others.
The grown-up individuals or adult child mostly has the patterns of lying, which are likely to be deceptive. Because they are in a situation to hide their own struggles and problems to the parent. To deal with an adult lying child there are many strategies, which may help them to come out with the truth in any situation of facing a problem.