Parent or spouse sponsorship (re cover letter and explanations etc)

Hi,
I am in the process of putting together the package with additional documents requested by CPC in november (the request that many of those still at the first stage got with the recent changes).

I understand that the forms requested (generic 008, family info and background one) are supposed to be completed and signed by my parents. As my parents do not speak English, I am doing it for them (and we will include use of representative form with me as their unpaid representative, I am also a sponsor).

However, now I am in the process of writing the cover letter (as we do need to provide some explanations and adidtional information on separate pages in our situation) and I am wondering how I should write it. I.e. should I say in the beginning that I am writing this on behalf of my parents and then refer to my parents where needed. For example, if I want to clarify something like 'during this time my parents did this and that" or "my parents do not remember this and that" etc... Or should I write the letter as if my parents are writing it, i.e. use first person. E.g. "During this time, I did this and that..." or "I do not remember my mother's city of birth" etc...?

THe latter is much more cumbersome (plus they do not speak english so it does not seem right) and I would prefer writing from my name but state that I am writing this on behalf of my parents and with their knowledge.

Wondering how others in the same situation do this... I guess a similar situation would be relevant for someone who sponsors a spouse who does not speak English...How do you write your explanations/cover letters?