I have scanned through all my Australian Wills indexes and found a John Wills who died on the 31st May 1902 aged 69 years. This was at Paddington, Sydney N.S.W.
I was unable to find a John Wills that died in Queensland in 1902 as you thought,so this may be the John you are searching for.
He is also listed on the Ryerson Index. This is an index of death notices placed in Australian Newspapers. The John Wills notice was published on the 2nd June 1902.
The website is http://ryersonindex.net/search.php
Type in in John Wills and you will see him listed.
The only way of knowing whether or not he is the right person is to go to your nearest Genealogy Library and look him up on the New South Wales Death index. This costs nothing . If he is the right person then I would send for his death certificate at website http://www.bdm.nsw.gov.au/
The fee for the certificate is $44 in N.S.W.
From that certificate it will give you plenty of details.
Hoping he's the one,