HI Clintus,
What an extraordinary blessing to have that opportunity to lead your Father to Christ!! "God was making His appeal through you - 'be reconciled to God'.
It really awesome also that you have enough compassion and empathy for your father to try and understand the pain of his affliction so you can support and encourage him.
The thoughts of OCD, though they are not valid and even though the person with OCD knows deep down inside that they are invalid, carry with them a component of such extreme anxiety that it's hard if not impossible for the person with OCD to ignore them.
The reason for the presence of the anxiety is a biological misfiring in the fight or flight center of the brain. This can be compared to having a fire alarm continually going off when there's really no fire.
So when a unwanted or disturbing thought pops into an OCD brain the anxiety center grabs hold of it and blows it up in such a way that the thought is percieved as something of extreme and imminent danger or importance. The person does the compulsive actvity in order to attend to the obsession, to try and get a reassuring feeling, or to try and undo an unwanted thought. When they do the compulsive activity it causes the obsession to get more stuck in their head, it gives it more weight and more validity, and then a viscious cycle ensues of obsession, anxiety, compulsion, more obsessing, even more anxiety and even more compulsive activity. The trick to treating OCD is allowing the obsession "to just be there", riding out the anxiety, and not giving in to the compulsive activity. Trust me, this is no easy thing to employ. It takes grit, patience, perseverance and a willingness to accept that you will feel worse before you feel better.
The anxiety can attach itself to different themes like health/germs/contamination obsessions, or relationship obsessions, or, for the Christian, obsessions over doubting ones salvations or unwanted blasphemous thoughts.
There's no way to cover all the bases of what it's like to live with OCD in just one brief post. But this is a very good place to gain an understanding of how it afflicts the Christian with religious OCD.
Other really good sources of reading on OCD that have helped me are two books called "Brain Lock" by Jeffrey Schwartz and "Stop Obsessing" by Edna Foa. Best online information on OCD, (actually best over all for me), that I've found can be found at
www.ocdonline.com
Read the articles by Dr. Philipson - great stuff.
God bless you. I'll be praying for your Father as he begins his new life in Christ.
Mitzi