Upvote:1
I met a lot of people here in Brazil coming from various countries by bus and they had no issues with getting tourist visas.
And, more specifically, according to Consulate-General of Brazil in Sydney website's checklist, you need:
Itinerary showing arrival and departure from Brazil;
And there is nothing mentioned about any flights neither in the checklist nor on the VITUR (tourist visa) main website, so your wife should be good to go! (I'm using the word should as the Policia Federal, the institution responsible for border protection, likes to change the requirements randomly, but formally you don't need a flight in.).