Apple Find My keeps disconnecting my contact

It seems everyone 1 to 3 days, my contact has to re-share their location with me. I do not have difficulty finding the phones of other members of that household. It is important that this connection stays intact. I use it to keep track of my elderly parent. They swear they are not changing the setting. Their phone is always on, their location services is on, and they are connected to wi-fi. Help!