It is possible to play an active role in caring for someone at a distance. The following links give several recommendations and references:
View or download these free, online handbooks give more detailed advice:
Aging Parents has a series of 4 podcasts / videos on Distance Caregiving (You Can Do It!, Your Support Network, Rural Caregiving, and When to Go). Links to audio-only podcasts are here (scroll down); or they can be viewed on YouTube:
Current technology can greatly assist caring from a distance. Please see the sections on technologies in Caring Basics and Caring at Home (these sources discuss apps and tools for being present remotely with your loved one).
Video calling software like Skype or Facetime can be a real boon, not just to communicate with your loved one but also to virtually join appointments (with permission) or for family conferences. Remote sensors that check for falls or whether medications were taken on schedule, and monitoring cameras that check location or activity, can provide some peace of mind -- but can bring up some privacy concerns as well.
Technology is ever-changing, of course. Those links will help give an idea of the types of technology currently available, but searches will find new products. Try to find reviews or product comparisons, if possible, before buying.
One fear shared by many long-distance caregivers is that their loved one might face elder abuse. Here are some of the warning signs of physical, emotional, or financial elder abuse.
If you suspect that a vulnerable adult might be in trouble, here are links to local agencies that can investigate and evaluate the situation.