Ok - I looked at pocket magnetic thingys.  Looks similar, but still has

a big endy bit like the tyre pressure gauge.

All of it is speculation really, til we get answers from the family

Was she diabetic?.

And - what's really the cruncher - we may never know what it is or used for!

That could do my head in

think we need a photo of its other end too

And in focus would be good hahaha

the clip part,that looks like it should go in a shirt pocket,can you depress that in any way?

like at the top,or does it slide down,and you haven't noticed,maybe?

A reset pen. Some electronics have a recessed reset button and the end of that pen would fit one IMO

I was also thinking reset tool but magnetic.

This is a magnetic pick up tool 

I also like the idea of something to do with lawn bowls if she partook in it.