He said Hebrew came FIRST, not that Matthew was ONLY in Hebrew ... he's wrong ... but it fits your purpose.
it would be good to read the Bible for one ...
I have translated most of the NT ... this is not the undergrad forum you are on ...
Here "One thing that is absolutely certain at this point is that the original language of the gospels was Hebrew, not Greek." --> the "original" / only language was Hebrew as per the poster and these were transliterated by the same
Now do go back and read and realise how many of your beliefs are equally wrong