Hopefully this makes sense to someone and I apologise in advance for the complexity of it all. Sometimes it does my head in

I am a British citizen by birth and my Belgian wife lived in the UK with me for several years since 2003.
We emigrated to Australia and both became Australian citizens (dual nationals keeping our birth citizenships).
We then, due to family issues, had to return to Europe, initially living back in the UK for several years then moved to Europe (moved prior to Brexit).
If I died my wife would like to live back in the UK but while I'm alive I'd prefer to remain living in Europe.
So my questions

Can she get a family visa to permanently live in the UK once I'm dead?
Does the fact that she used to live in the UK and she still submits UK tax returns help her get any long stay visa?
She wouldn't be working (we're both retired).
Many thanks in advance,
Richard