It's either that or he just says stuff to troll a few people. Remember that he had been hiring contractors to construct or renovate large buildings for decades. He should already know that making Alcatraz a useable structure could be cost prohibitive.
Much easier said than done. Would it be more cost effective to just build a brand new prison than renovate, retrofit and upgrade a crumbling old mess like Alcatraz?
https://www.google.com/amp/s/www.nbcbayarea.com/news/local/trump-order-agencies-reopen-alcatraz/3860304/%3famp=1
If anybody starts manipulating time and space, how would we know? Our thoughts and memories are kept in time. Change anything in history and our memories will change with it.
If anybody spreads bullshit, it eventually gets found out in a free society. That's the marketplace of ideas. In places where the government controls the whole marketplace, it's too often that the bullshit prevails and the facts remain hidden.