Trailer collapsed on my Son's legs last night

So I rode with some friends at Ray Roberts (Far North Dallas, TX)yesterday evening. My son came along even though he didn't ride that evening. He is 9 and likes to help me with getting the boat ready, wiping it down, and helping with the trailer. He's gotten really good at handling himself around the boat and can be a big help. Safety is number #1 when he is with me. He knows where to stand and where not to stand at all times when backing the boat up. Well after backing my boat into the storage unit last night. I was on the boat picking up the rest of our things while Trent (my son) and my friend were disconnecting the trailer from the truck. Trenton was cranking the jack and next thing I know....BOOM... the boat CRASHED down and my son is screaming. The swivel trailer jack had not locked into position and the trailer had collapsed onto my sons legs. I leaped out of the boat over to my son and couldn't believe my eyes. He was pinned under the trailer. My friend and I lifted the trailer and at the same time I was able to pull him free. I just assumed both legs where broken as I loaded him into my truck. I laid him down and was amazed. There was no blood, no breaks, just a large abrasion and what will be a large bruise. Because of this we skipped the ER and went home to ice it down and give him some Motrin. As you can imagine he was very shaken up. I am not one to get on a message board and preach, but I witnessed a miracle last night. God was watching over my son. His legs could have been completely sheared off from the force of the trailer with the VLX crashing down on him. At a min...legs would be broken. Nope, nothing but a bruise. Amazing. I pray for my son every morning for his safety and protection. I believe my prayer was answered. Lesson learned on my part of course. My son will have nothing to do with helping disconnect the trailer. He can stick to wiping the boat down.