My question would simply be how does he know the torque values that he alleges were wrong and even if they were wrong how could that compromise the integrity of the glass?

It isnt frivolous - a significant event occurred that was not normal and the claimant states he suffered mental and physical injury

It isnt vexatious - as above, and in many countries courts apply it to litigants who repeatedly claim or continue to claim unreasonably. This is an initial claim with no evidence of previous claims

That still leaves the Courts to decide whether to make a judgement in his favour, or the defendants to decide they want to settle before a hearing....

No, it's not vexatious in that specific sense, but more generally the term can be understood as "denoting an action or the bringer of an action that is brought without sufficient grounds for winning, purely to cause annoyance to the defendant".

That sums it up pretty well IMHO.

I find it rather telling that he didn't become 'injured' until after the event was over. He was safely on the ground before he found out what had happened and suffered the 'injury'...

That is quite possible

I have been commenting on the system. I think it unwise to make comments on the individual parties based on press reports and one document. That is for the Courts