CTjeff,

Welcome to the forum.

I'm not a doctor, so take this post as you will.

If I understand your post correctly:
- your father went 5 years without levodopa. Was he on some other medication?
- your father went 3 years with levodopa, with no sign of Parkinson's symptoms. What dose was he on?
- over 2 years he has become immobile. Did your father's doctor try increasing his dose of levodopa during this time?

Some deterioration with time is to be expected, but I'm surprised by the large change in the rate of progression.

In my opinion, this suggests that your father had slowly progressing PD for the first 8 years and has had a much faster progressing "something" for the last 2 years. Has vascular PD and depression been discounted?

Have you discussed this with your father's doctor? It could be something other than IPD.

John