Recommendations for GPS device?

Hello,

I am new here. My father is in the late stages of dementia but still living at home with my mother until we can find an adequate assisted living facility for him. He has started to leave the house and wander so I am growing very concerned for his safety. We have alarms on the doors and cameras on the house but my mother isn't always on alert when he leaves the porch and goes into the yard.

I am looking for suggestions for a bracelet that he cannot remove that will allow us and emergency services to locate him by GPS if he wanders into the woods. Specific brands to try or to avoid would be greatly appreciated. There is a lot of over-priced junk out there I would like to avoid. If you have experience with such a device any information would be much appreciated. I just want to keep him safe. (it has to be a bracelet - he will not tolerate anything else and often removes his clothes and shoes). Thank you in advance for any responses.

Monica