Move out notice laws

1.A promise needs to be in writing to be legally effective, and used in court. An e-mail would do it.

2.Your parents are not liable to seek alternative accommodation, should your actual arrangements not be deemed suitable.

3.Most of the applicable law applies to accommodate heirs to a stable living place, assuming she owns property and you are a direct living heir, that's  article 1.831 of the 2002  Código Civil. 

If means are not impediment, but the timeliness to move out, then you need to work a reasonable departure date, other than to seek legal confrontation.  That alone would sour your relationship between you and your parents beyond repair.

4.Local tenancy laws have no provisions against evictions of parents with an infant. However, if you are meeting the requirements for tenancy, then you have the right to stay, despite nuisance that may be caused by your child.    You have to prove you are current with your obligations as a tenant to your parents.

I am not aware of your marital status, or your ability to actually get a a job in Brazil to support yourself and your child.   

I will assume, single mother, child out of a wedlock, decided to move with parents to ease the burden, the child is a toddler, etc.  Please correct me if I am wrong....

But here are the implications on your situation.....

Being alone with a child, with no family support, will make harder on you to actually earn a living. You will need surrogate parents for baby sitting, if you manage to get an occupation or lively hood.

Unless you already have a position under contract, you will find ever harder than making ends meet in Brazil than in the US. 

  Most Brazilian  single mothers without decent employ and frayed relations with parents will be confronted with the dire proposition to either not being able to cover living expenses, or resorting to prostitution.  That choice alone, assuming a menial or unskilled job ( retail clerk, office adm assistant, working in a call center ), means prostitution translates in earning as little as fourfold .

I would guess, a significant portion of working girls ( 70% ) that "ply the trade" are single mothers.   

You always have the option to return to the US . Conditions there nowithstanding are far more favorable to working moms than they are in Brazil. 

if you decide to stay, may i suggest you to make mends to your parents, and work on disciplining your child behavior.   And bid time for an eventual move out situation. 

In short, you will have to eat crow.