Do you even go outside?
You can perform a check without shining a UV light on anybody’s skin.
I work nights 
Edit:
OP, here’s some more info for you.
“The UV-A LED flashlights and “black lights” evaluated to date by APHC (Prov)’s Nonionizing Radiation Program (NRP) pose some risk, but would not cause injury during normal use. The safety limits would only be exceeded if prolonged or many repeated exposures occurred. ”
Often what happens is Science finds out long term exposure to UV light is the cause of skin cancer. Before then, everybody wanted the darkest tan possible. Nobody can say UV rays are not harmful, but harmful items are used all the time in medical treatments. Dangerous levels of morphine for terminal cancer patients for example. In this and other cases a risk/benefit analysis is the way to get the answer. Is the minimal risk involved worth it for the benefit of having a more comfortable patient. If the paitient is 22, maybe not, but at 99, there is just not enough time left for cumulative damage. My Mother is 93, and if she were bedridden I would focus more on her comfort that avoiding things I know can cause harm with long term use. I worry we as a society worry to much about trying to extend life by haveing the paitients final days be spent in misery. Some have even refused to issue more morphine to terminal cancer patients from concern over addiction, which is ridiculous. If my Loved one is in agony with final stage cancer, I could care less if the die an addict, but not in unbearable pain. Compassionate care of those with terminal illness or extreme age should overide the fear of long term harm an device or drug might otherwise involve. I am sure the OP wishes the Father to live forever, but he wont on this earth. At 99, I think the comfort, and quality of life in his remaining days are more important than possibly harmful UV rays or medications. I am 62, but in very poor health due to a damaged spinal cord. My Family(sister) knows that near the end, to risk exrtra life in favor of decreased pain and greater comfort. With my current quality of life, I do not even want to live to be very old, because my quality of life already sucks.
If you are asking me that, I usually only go outside to go to the mailbox. I go a month at times, never even seeing another human being. I do communicate with them by phone or on forums.
He is technically right, it should not cause harm if the exposure is brief, but you can expect the intensity is around 10-20x of bright sunlight, which could theoretically be problematic
It will probably be fine if the exposure is brief. I would want to use a less intense, diffused UV light if it’s being pointed at skin tbh.
UVB and UVC are much more likely to cause cancer, though technically we as well as birds require UVB to make vitamin D
probably the light is safe, the power levels are low, time is short, it seems to not be UV-C
what i doubt though, is if it will show you anything
you will definitely not explicitly see ‘germs’ or ‘dirt’
things will glow or not
and you will not really know what they are
pee for instance has a faint glow
but so does the bluing from laundry detergent and some soaps
underwear lint
if the UV has too much blue or purple, then all kinds of things glow, obscuring anything that you might really care about
i just would not expect to learn anything, though the risk is in my opinion, low
you just do not know what you are seeing, usually
or missing