I read the court documents for the trial a while ago. There were two issues:
1. They quoted the statistics assuming the deaths were independent (i.e. the squared the probability of one SIDS death). The error of this was pointed out.
2. No one mentioned the prosecutors fallacy.
In the end the jury were won over by an argument along the lines of: "Ignore the statistics. You *know* it's really unlikely that these were two SIDS deaths.".