The ninth season reveals new events, as Dan attends and secures a temporary stay for a short time due to his restaurant, which has been badly burnt for a short time. Dan was living, but he may have burned it before Nathan tired of trying to join his sister's family.
Even though it started as a relatively run-of-the-mill teen soap, it's become a lunatic fiesta that would make a daytime soap blush and makes the racier ABC Family dramas look like guidebooks to being Amish.
One of the best takeaways from the series in general - is that they have all learned from not only their own mistakes, but the mistakes of their parents.