Should you avoid taking pictures of elderly friends and family?

Elderly people are fully aware of their mortality. They may perceive this as you wanting to remember them when they are gone but each culture handles this differently so maybe it makes sense to ask other elderly people from your specific culture for their opinions.

My generalized opinion is to just be tactful and sensitive. They are old enough to know your intentions. They've already lost many of their friends. Get them to show you their photo albums and maybe take some pictures of their pictures or make a video of them talking about people in the pictures. Ask their permission where you may post the video you made, such as only sharing with family members privately via thumb drive or if big brother social media is ok. I prefer self hosted private family forums. Whatever happens give them a hug, it's worth more than anything you can say.

As one who is nearing "elderly" status, what I have learned not only in myself but from others who are my age or older is that younger people tend to be much more upset by the reality of aging than older ones. We've had years to come to terms with and plan for the inevitable future.

Take photos of all your friends and family all the time. Any day might be their last!

But to reply to your questions, the answer is yes - take photos but do it in the proper context

"May I capture memories of {you}|{us together}?"