Elders can be protective of their independence. I'm not sure which is harder; one that won't accept hep, or one that expects you to drop everything and wait on them hand and foot. (My mom was the latter.)

There are some caregiver subreddits that may help you figure out the best way to get your parents to accept help. The techniques that seem to work the best are the ones when they come up with the idea on their own. But this requires quite a bit of finesse. Also, they might grumble, but I guarantee they are secretly grateful.

Can they do any kind of face-to-face time? There are a lot of options and you may be able to get a fairly automated protocol set up so that you can keep contact regularly.

Best wishes to you.