I hope his passing was gentle and your family is doing well.
My husband was an independent for most of the time I knew him. He even voted for Reagan in 1980. Over the years, he became more and more liberal, to the point I'd let him fill out my sample ballot for me. He had more time to read than I did, and I knew I could trust his judgement on issues and candidates I didn't have time to research. Still, he remained registered as an independent.
Then came the 2004 primaries, and he was so jealous of my Democratic ballot with Howard Dean, John Kerry, et al on it. He finally registered as a Democrat. He died much as your father did in December of 2004 after only six weeks of becoming symptomatic with cancer. But he died a Democrat. I still have his change of registration card on the fridge.
Maybe he and your father are discussing Dionne and Krugman right now.