Yes he can sponsor you. Yes you certainly have a chance! There is NO financial/employment requirement for spousal sponsorships. I am in the process of sponsoring my husband and I have not worked for over 10 years as I was the homemaker while my husband worked. For the past two years I didn't file any tax return either because I wasn't making any money and living in the Uk. So YES, he can sponsor you regardless of employment, tax returns, or income amount.
However, there are a few things you need to do when compiling your application:
1. The sponsor has to supply evidence on how they intend to support you throughout the application process. So I would include a written letter by the sponsor explaining how they intend to do this i.e. now have a job, savings, family support, accommodation, job searches, etc. Include a written letter by sister where she states that she is willing and able to provide support in terms of financial, accommodation, utility bills, etc. or whatever she is helping you with. (this written letter by the sister providing financial support is the most important thing to include)
2. They ask for a Notice of Assessment from the sponsor. As he does not have one because he didn't file taxes, you have to provide a written statement as to why there is no NOA included. i.e. was not working for the past two years, only just got a job, etc.
3. I would get his new employer to write a letter confirming employment and the wages he is getting. Include this in application along with a paystub.
I believe that's enough. Perhaps other's can comment more as I'm more familiar with IN Canada applications.