Hello and Hi to all mums out there!

I am posting this question to help me out to advise someone close to me so that she will not get pregnant.
My sister is already 40 years old now and she is till using an oral contraceptive pills because she doesn't want to get pregnant again. The pill she's been using right now is the one used for the breastfeeding mums. Her baby now is going to be three (3) year old this May and just stopped sucking milk from her.

Is it still safe for her to use that kind of pill?
What kind of contraceptive is best for her?

I hope to hear from any concerned mum out there.

Thank you,