7.30am is extraordinarily early. I have never heard of visit at that time - prearranged or otherwise.
I have observed that some make a special effort to visit people during public holidays - but this is generally an hour or two later - like 10am or 10.30am - never earlier.
Without context, it is so easy to misinterpret a discussion. Just a thought -is it possible that they were encouraging your elderly friend to ensure that he has arrangements in place to ensure his wishes are followed thru? This is something a family member would ordinarily assist with, and you did say he had no family? Is it also possible that your friend was requesting personal advice on the subject? A step further - is it possible he was asking them how he might arrange for a contribution to be willed to the organisation of Jehovah's Witnesses? None of those contexts are evil or out of hand.
"My father has had nothing to do with Jw's for over 70 years and when he becomes quite ill and old they surface."
Let's break that down :
1. "My father has had nothing to do with Jw's for over 70 years.." - that you know of. He may have been accepting calls from time to time for some time without your knowledge.
2. '... and when he becomes quite ill and old they surface." - nope! They visit every home with a view to contacting every person they can on a regular basis - they aim to speak with all people.
If they are not home when they call, they usually try at least two different times, and if still not at home, might leave a small leaflet or tract to show they tried, then try again when that map is re-issued - likely some months away.
It is also quite possible that with the changing condition of your father he may have mellowed. Where he once made no time for them, he now did so - perhaps even relishing those visits.
A real sadness is that after a couple have worked their life to provide for their own, instill values in their children to set them on a good path with them now having family of their own, that just when these ones are now time and often asset rich in retirement, their minds bright and filled with wisdom from experience and a desire to pursue personal goals their former circumstances did not allow, that now their bodies deteriorate around them - the hearing and sight fades, medical matters dominate topic of conversation, the knees wobble, and all those hopes and dreams for a planned retirement of adventure together is replaced with a long period of loneliness and relative isolation before succumbing to that great enemy, death. That is the sad reality for most.
I also understand that on Christmas day few have any desire to celebrate what the occasion is reportedly about, but are more interested in their own entertainment, socializing, getting and receiving gifts, seediness from revelries of the night before followed my more to come.
With cars to pack, kids to prepare, eski's to fill, salads to prepare, places to go, BBQs to light, visitors to arrive, etc etc...
Has Santa been? What did he leave me?
Yeah - Christ is the LAST person on most people's minds at Christmas ! Those pesky Witnesses.... lol