Invitation letter(B2)

Hello:

Last year I sent my baby son to china, now I want to invite my mother to come here with my son. My current visa is H1B. I am not sure whether I should mention that my mother will send my son (almost 2 years old) to here in the invitation letter.

My mother will go to Shanghai us-embassy for applying visa.

Any information and suggestion are appreciated.

Thanks

HS