What can a sentence be for a convicted felon be charged with possession of firearm and ammonition?

my boyfriend is on probation doing very good on it. he was just at da wrong place at the wrong time. He has a record of things like domestic violence and traffic violations so this would be his first serious charge if he's convicted of it. Would be the first time of possession of firearm but he is a convicted felon tou. The shortest way of the story. He went to a friends house to put some of his belongings in the house and while he was puting things in he saw in a closet their was a gun that's registered to his cousin and so he touched it, he tought it was broken so he was trying to fix it so as he was trying the gun fired off up in the ceilin, neighbors got worryed but he apologized an explain to them it was an accident the neighbor was ok and went back on his business. Till the next day his cousin went over to the neighbor and started a problem with the neighbor and they had a domestic violence going on and by this time my boyfriend left the place hours ago. So the neigbor calls the cops and then next tang you kno my boyfriend becomes the main person being charged while nothing is happening with the real domestic problem. Im jus really confused im 32 weeks pregnant and have a 3 year old and we had alot of thangs plan and im stressin out on this i really need to know how can this problem be solved in a good way. Please anybody know or has been in this same position..i really appriciate your help!!