This is a common saying in the Spanish speaking world. Recall that a saying is a short, pithy expression generally containing advice or wisdom. So this phrase means in English better late than never and means that you arrive or do something later than expected and this is not good, but it's better than not at all. This phrase is often expressed with sarcasm saying something positive but remarking on someone's lateness. So:
What do " The grandmothers of Plaza de Mayo do? They look after the children who were kidnapped during the dirty war. They fight against those who kidnapped their relatives. They are looking for their relatives who were kidnapped during the Dirty War. They govern small communities in Argentina.