Re: Spotting scope for 100 yards?
Agree with it being a personal preference as far as straight/angled goes.
I fall into the angled for everything camp.
Question for ya, will Dad ever want to use his new scope from his vehicle for watching wild life or what not? If this is an option you may also consider a window mount with a quick detach shoe that also fits his tripod. For in vehicle use, I find an angled scope with a rotating ring on the body of the scope, allows me to get the scope in a position I like. With a straight bodied scope you have to get right behind it all the time. Guess I just like the versitility of an angled body scope that has an adjustment ring - it gives you alot of options for finding a comfy viewing angle, be that at the range, your back yard, in a vehicle.
As we all get older, the fact is that our eye sight deminishes and you need more light to your eyes to see the same things that younger eyes see with less light. That said, I'd opt for a scope with a larger objective for older eyes. Something else to note if you Dad wears glasses is the eye relief of whatever scope you look at buying. The longer the relief, the more room you get for glasses. I wear glasses and my scope has 18-20 mm of eye relief. This works out just fine.
Bushy, Vortex would be where I'd start. You don't have to break the bank, but in many regards you get what you pay for. Buy the best you can afford and Dad will be good to go. Going too cheap will only result in being hard on your dad's eyes and make your pocket book lighter.
I have a buddy who just raved about the $99.00 Barska kit he bought at Gander Mtn. Did it work at the range? Yes, but the image was fuzzy at 100 yds. Yeah you could still see the holes, but it was hard on my eyes. I've since let him look through my Vortex Razor HD. No, not really a fair comparison at all, but it made him realize that his Barska wasn't such a great deal afterall.