I don't really follow why your parents would ask you, as a non-Mason, what we, as Freemasons, are part of. However on the understanding that you are now asking us for them please share, with them, the following:
Freemasonry is a many faceted Fraternity that has existed for over three centuries and which has been copied all over the world and as a result it has many many divisions that all agree on the importance of fraternal fellowship amongst good men regardless of their background. However, mainly due to its age its method of introducing new members is laced with moral imperatives that it expects its members to take to heart and act upon in their normal lives. A part of these encourages charitable acts and thinking among us.
Freemasonry is not a Charity nor is it a charitable organisation BUT it is responsible for the existence of Masonic charities around the world AND each Master Mason contributes money from his own pocket to many Charities and charitable organisations and many of us also go further in actually giving our own time to the same. The same is true of each individual Lodge around the world