The thing attaching him to the egg will fall off on it's own. Sometimes it takes a while but is usually just pops off on it's own. Congrats on chick #2!!!
Your humidity will go down as the chick dries off. The chick peeping and walking around always seems to stimulate the other eggs and get them to hatching too. Don't open your incubator because it seems that you have perfect hatching conditions going on and you want it to stay that way.