Is he really a professional in what he claims to be? I find it so hard to believe.
He sort of was, up until about 15 years ago. He does hold the degree he claims, and he has been professionally employed in the marine shipping industry. On his c.v. the only engineering role listed is that of service in the Swedish Navy in 1970, which would have been his first job out of college. From 1971 to 1999 he seems to have held jobs for marine insurance companies as an inspector of ship damage, though he does not seem to have been involved in ship building directly. However, assessing damage done to large hulls does require engineering knowledge.
From 2000 onward his verifiable professional activity is limited to his self-employment company, which in turn seems to do little more than publish his conspiracy theories. It is safe to say he has no creditable professional activity for the past 13 years.
And yes, it is difficult to believe that someone who displays such an egregious misunderstanding of the behavior of the physical world could ever have been any sort of engineer.