[civil_engineer]

If he represented himself as an engineer or engineering expert in a legal proceeding, well, that’s where he may have made a mis-step. Even if it’s on behalf of his son. Maybe, he should have prefaced every sentence with IANAE, but…

[chiph]

That's what he did (mentioned in the article). He prefaced his testimony with that he was not a licensed engineer but had worked in the industry for many years.

A better question would be whether he had done piping & fluids vs. another civil engineering specialty such as bridge design.

[carlmr]

I think this preface should be enough, he didn't claim to be something he isn't.

[morelisp]

The fact it's his son makes it looks even more like testimony from convenience rather than professional consideration.