Sulayman bin Yasar (may Allah have mercy on him) says: Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) married his son to his brother's daughter while his son was still young at that time, and no dowry was fixed. After living for some time the boy died, and the girl's maternal uncle brought the dispute with Ibn Umar before Sayyiduna Zayd bin Thabit (may Allah be pleased with him). Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: I married off my son intending to do good for him, but he died before that, and no dowry had been fixed for the girl. Sayyiduna Zayd bin Thabit (may Allah be pleased with him) said: The girl will receive inheritance if the boy had wealth, and she must observe the waiting period, but she will not receive a dowry.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14419