Originally posted by aoeu If he is familiar with a Canon PowerShot camera . . .
Buy him another one. No sin there. I own two and like them. . ..
Gotta agree with quoted post. My Dad is 94 today, still drives, votes, does yard work, but.....struggles to operate the TV remote, the new electronic oven, anything tech. So although I totally relate with you wanting to get him something "better", from my experience, he wonʻt use it or may get frustrated with anything other than auto modes.
If he has a Canon Powershot A710 (7 MP) or the SD700 (6 MP) are both 10 years old now and typically had a 6x zoom.
The Canon Powershot SX720 is well within your budget with 20MP and a 40x optical zoom, but is small and compact and the interface should be similar for him.
Canon PowerShot SX720 HS Digital Camera 1070C001 B&H Photo Video
As his old camera is silver, he may like the looks of the Nikon Coolpix A900 also 20MP with a 35x optical zoom.
Nikon COOLPIX A900 Digital Camera (Silver) 26505 B&H Photo Video
And optically, Iʻd go with the Sony DSC HX90V with 18MP and the Zeiss 30x zoom.
Sony Cyber-shot DSC-HX90V Digital Camera DSCHX90V/B B&H Photo
There are Lumix that are better, but at least $200 over your budget and Iʻd say they with Sony are better with video.