As a Muslim and lovers of Prophet Muhammad (PBUH). We should have known the sons of Prophet Muhammad and his other daughters. All the sons of Prophet died at a young age. unlike the daughter of the Prophet who grew up and married.
The Sons of Prophet Muhammad (PBUH)
Al-Qasim bin Muhammad
The first child of Prophet Muhammad (PBUH) was Qasim bin Muhammad bin Abdullah the first son of the Prophet who was born before Muhammad was appointed Apostle of Allah SWT. Starting from here the Prophet got the nickname Abul Qasim. Unfortunately, he died when he was a very young age of about 17 months or two years.
At that time he was still breastfeeding and was able to walk. His death occurred before the prophethood, even though there is an opinion which states that the death of Qasim occurred after the Prophethood which roughly coincides with the year 605 AD.
Not just the mother (Khadijah) who was sad. The Prophet also deeply grieved over the death of his first son. This is why then Allah SWT entertains and reminds the Prophet with the descent of Surah Al-Kauthar verses 1 and 2.
Indeed, We have granted you, [O Muhammad], al-Kawthar. So pray to your Lord and sacrifice [to Him alone].
Abdullah bin Muhammad
Abdullah was the second son of Rasulullah who was born by Khadija. Abdullah was also given the name Al-Tohir (the clean) and Al-Toyyib (the good). The reason for this extra name was that Abdullah was born after prophethood. Some historians claim that Al-Tohir and Al-Toyyib are two names for the sons of Prophet Muhammad PBUH other than Abdullah.
Abdullah is the siblings of Al-Qasim and both were born in Makkah. He died while a toddler as well and was buried in the same city.
Ibrahim bin Muhammad
Ibrahim was the youngest son of the Prophet and his half-brother with Qasim and Abdullah different from the mother. The mother of Ibrahim is Mariya Al-Qibtiyah. He was born in Medina in Dzulhijjah year 8 Hijri or 630 AD.
Similar to the other two sons of the Prophet, he also died as a toddler. He died on Jumadil Tsani in 10 Hijri or 631 CE at the age of 18 months.
Related article: The brief story of 25 prophets
Why the three sons of the prophet died
The death of the three male sons of the Messenger of Allah, who are almost uniform under the age of two years invite question marks. Moreover, it did not happen to the daughters of Rasulullah. They reach adulthood and even marry as well.
The definite answer is God is all-knowing. It’s God’s secret stored in Lauh Mahfuz. One of the most important opinions about the wisdom behind the death of the sons of Prophet Muhammad PBUH is as follows:
The suggestion that sons of Prophet had grown up would be a Prophet. Had the sons of Prophet lived to adulthood, he would undoubtedly become the Prophet after Muhammad. When this happens, it means that the Prophet is no longer the cover of the Prophets and Messengers.
 Ibnu Hisyam, Al-Sirah Al-Nabawiyah,1/190