I'm not going to link to it, but the POTUS posted overnight about this, and even by the standards of that particular social media account, it was probably a new low. Someone in another forum I read regularly said of it "I'm going to show this to my kids to help teach them what the word sociopath means". It's not even the usual "politicizing a tragedy", just the complete inhumanity and self-centeredness on display. Look it up yourself if you want, but bring a bag.
I don't take from it personality judgements, so much as it makes me want to look into how Reiner was trying to develop a series called 'The Spy and the Asset' on how Putin and Trump met and began working together.
That tracks for me, so Trump has personal reasons for behaving the way he does, though arguably self-preservation would induce him to not carry on the way he has done. But then he cannot be quiet about things he's guilty of, so I can't see his behavior as anything other than having a motive for just what's happened. I can't imagine he would take Rob's proposed series with equinamity: I'd love to know what Rob knew.
To elaborate a bit for those who don't want to go read that sort of thing: Trump said Reiner was killed because he made people so angry by being opposed to Trump. There were a bunch of asides about Reiner's talent and mental state, and it closed with trying to brag about (fictional) administration accomplishments.
Trump's a piece of work, all right.