Short answer
Dowry from the bride's family is not an Islamic condition for Nikah.
Islamic Guidance
What Islam teaches
Islam places the responsibility of Mahr on the husband toward the wife. Demanding money, goods or property from the bride's family should not be confused with Islamic marriage requirements.
Practical Guidance
What you can consider
Families should avoid making marriage conditional on dowry. Wedding expenses and gifts should be voluntary and reasonable rather than demanded as a condition.
Sources
Qur'an 4:4; Qur'an 4:19.