Best tracking history option or app

Hi: I'm not an iphone user but tech support for a friend with one. She's now lost 3 iphones in 5 years. I'd set them up with the find option on her AppleID account but, by the time she'd realized the phones were gone, the battery had died (I assumed). I'd also activated the 'lost' option and put in a phone to contact but, as in the two previous cases, nothing... .

She's also got a bluetooth (?) chip attached for around the house but that didn't work, indicating it's somewhere in Rest of World or the battery is dead there too.

So, what's the best way of looking up her travel history to at least get close to where a phone was or might be, even if the battery is dead? Ideally a fairly cheap app. I've looked at some of the assorted family type apps but all I think needed here is just the ability for an online location history that I can access (with her permission of course) remotely.

Ideas appreciated!

Thanks,

George