This is great and a brilliant way to push people to hit there goals. Im sorry to hear about your dads health but its great you have found the determination to push this challenge.
100 push ups is a great start for anyone. I will attempt this this weekend and report back to this post. I can assure you this wont be anywhere near the 100 mark, i will however start upping this per day to see where i can get to. It would be great if you did a post about the benifits of push ups and which muscles groups are targeted.

Ash