It's case to case basis, in my experience doing the sv app of my mom, I put zero in funds available in the form, in my view this is the funds in my mom's name, zero, coz she is unemployed and our dependent.I still don't understand the logic. If I am saying that I am going to be responsible for her trip expenses to/from/in Canada and even her lodging and boarding expenses I think it does mean that the funds I have in my account are available to her and the logically right answer to question "Funds available for my stay(CAD)". As far as the financial ability is concerned, that is to be supported by employment letter/NOA/T4 etc and my bank statement which is not only going to prove the amount entered under Funds available for my stay(CAD) but also the financial ability.
I think if one is meant to financially support a trip by him/herself then that's to be the amount in individual's own account.
I may be wrong on my understanding on this matter but this is at least what I was standing by up to now.
One more question, invitation letter and promissory note can be all together one single letter or they have to be separate?
I submitted my NOA and my husband's NOA, I did not submit bank statements, still approved.
In you case, if you want to submit bank statements to make the app stronger, you can.
Invitation letter is addressed to your parent
Signed promise of financial support is addressed to CIC
if you apply online, you can merge these two in one pdf to be uploaded in invitation letter tab ex:
page 1: invitation letter
page 2: signed promise
page 3: your ID like PR card photocopy or Citizenship certificate