The other notable thing is the mix of upper and lower case letters in his writing. This is one of the symptoms of a learning disability called Dysgraphia.
I'm no expert in learning disabilities but Trump certainly comes across as someone who struggles to organise his thoughts and there are many reports that his briefings have to be in bullet points which would suggest he has difficulty processing language.
I know people with learning difficulties can and do make a valuable contribution to society but I'd say it's certainly unusual for such a person to be President of the USA. One would expect the ability to process large amounts of information quickly and accurately would be a prerequisite.