brazilian trying to get a visitor visa for canada

[figgy]

I'm hoping someone on here has some advice I could give my friend. She is Canadian living with her Brazilian husband in Brazil. they have been living in Brazil for 1 year and prior to that 3 years in the UK. they want to visit Canada for Christmas, as he has never been before but his visitor visa was just rejected! they said he didn't have enough income tax documentation. he has been working in brazil for about 6 months as it took him a while to find work.

does anyone have any advice I can offer them? can they re-apply, why is it so difficult for brazilians to just visit canada?

any advice would be amazing as they are both very upset that they cannot come here for christmas.