When we are first introduced to Liam, he is instantly charming with his swagger and his confident personality; this stays with the character throughout his entire story.
Liam has no single solitary clue about any of his family members. So, for all he knows, he is alone in this world. As a result, Liam has adapted to this world in a way that he does not have to rely on others to succeed. This is a good thing because he is a capable character who is strong in himself but is also something he needs to learn to outgrow because he is sometimes distant from others.
However, Liam does claim the "big brother" role of the group so he is very protective of his current family. This leadership role is challenged by other characters such as Elektra and Liam does not let it go easily. I admire the character for this, he is not one to back down from conflict easily and this is something which we should all take on board in ourselves to be stronger as individuals.
Later on, Liam does discover that he has a brother and eventually goes to live with him. We feel happy for Liam because he has always had this essential piece of life missing from him but now he has a chance to complete himself.
We as the audience do not see Liam for a while but when he finally returns, his entire arc is expanded upon greatly. Liam has made some mistakes which has put his brother's job in jeopardy. From this, we learn that Liam has grown close towards others which completes this arc in his life and due to this change, he feels guilty for potentially destroying a part of his brother's life. Liam no longer feels bad for doing something that makes him appear in a negative light but instead feels bad for doing something that puts someone else in a negative light. I am sure there have been many instances in our lives where we make mistakes which impact others in a bad way so we can relate to this. Consequently, Liam runs away from his problems, which I am sure many of us have done as well. Liam in the end does reconcile with his brother and the viewers are given a satisfactory conclusion.