People will make conspiracy theories about anything. I agree with Kelly, it's best to just ignore, and move on, rather than risk a ban over something so stupid. Not too long ago in a political thread someone randomly said the bible was a guide to ethnic cleansing, and ranted on Christianity for utterly no reason. It angered me, but it wasn't worth getting banned arguing over it because it was so utterly asinine. So I ignored it, stayed out of the thread, and moved on.
As for the guy laughing, it's understandable. When my Grandma was on her deathbed, I spent hours by her side constantly tense. Something funny came up on a TV another patient was listening too, and I laughed. I saw her take her last breath, I was in a state of shock, and just stared silently. It wasn't until the nurse officially checked her pulse, and announced it I broke down. Even then, I held a lot of it in. It wasn't until I got home that it really sunk in, and I cried, and thought about her, prayed, ect. I got a lot of it out of my system that night. I was still depressed, and thought about it a lot, but didn't spend the next day crying the entire time.
My guess is that that father did cry his eyes out. During that news conference someone told him something funny, and he laughed. We all need a break from the sorrow during traumatic events or we'll completely drain ourselves. Then when he went to give his statement to the press, the weight of what he was about to say hit him, and the seriousness of it took over.
You don't have to be an actor to pull that off, just human. It's too easy for random people on the internet to set back and judge everyones actions in videos on youtube in slow-mo, and come up with crazy ideas about each facial twitch. It's another thing to be someone who just lost their child, have cameras shoved in their face, and be expected to give a few paragraphs to sum up what their child meant to them.