There are a number of possible explanations to this, ranging from the officer wasn't sure he was intoxicated and wanted to watch him a little longer to there was no safe place for your husband to pull over so the officer had him keep driving. It could be a crucial fact to your husband's case or it could be totally benign, without knowing the whole case there's no way to know for sure. What I can tell you for sure is that if your husband was charged for DUII he will be offered the chance to speak with an attorney, and he should find and speak with an attorney (either a private attorney or a public defender) as soon as possible. That attorney will go over all the facts and all of his options with him and he can go from there. Finally, please don't post any more details of your husband's case online and neither of you should talk about the details of the case to anyone except an attorney, even to each other. Good luck.
Interesting for sure! As my colleague mentioned, don't post any more details on the internet as anything you say may be used against your husband but do get in touch with an attorney as soon as possible. Talk to a few different DUII specialists and get someone in your corner as soon as you can. it sounds like an interesting stop! Good luck to your family.