Larry had absolutely no business being in that courtroom.
No one knew absolutely that he was the father EXCEPT Howard and Larry (sperm donor). Hell, he's not even a family friend at that point.
LB’s purpose in florida should only have been obtaining Anna’s dna (which was postured on the ‘hair-dying’ allegation). Still can’t figure out why he ws surprised that Dl had brown hair, not blond (neither he nor Anna are ‘natural’ blonds) and, imo, his ‘blue’ contacts are too blue and photograph unnaturally imo (although they do tend to mask pupil size). there was no need for anything else, including his ‘custody court’ type-testimony, until parentage was settled.
otoh, his testimony did give us some meat to chew on, at a time when HKS and crew were starving us for information, and I’m sure he realizes in retrospect it was a Big Mistake to take the stand for exactly that reason.