Sorry, but in the UK AAIB reports ARE admissible as evidence in court.
The AAIB may be required to attend and to be cross examined on the content of the report.
They will be treated as a expert witness.
Please see
Rogers v Hoyle: legal victory for claimants in UK aviation claims
You will note that the original decision was appealed and the appeal court agreed with the lower High Court finding that AAIB reports were admissible.
This is now legal precedent.
I hope you all now understand why I earlier said that the unfortunate pilot should say nothing whatsoever without legal representation.