who's name be put into the title of the inherited property? the children of the deceased owner or the wife?

My brother died 6 years ago with three underage children left. I did all my best resources to help the two kids finished their high school education. The youngest child is with my mother continuing her studies and is now in her 3rd year high school. In short, we took care of the three kids with all our money and support, while the mother works in a canteen here in Manila with no responsibilities. The sister-in-law who is now in his late 30s is already living with another man 20 years older than her, and is still possible to get pregnant.

Now, my question is this: My mother is now dividing our residential and agricultural land to us 6 siblings. Since my brother is already dead,

1. can we name the property under his eldest son?
2. At what age can he be legally put his name in a land title?

We're afraid that if my sister-in-law got pregnant, she can divide the inherited land amongst her children with her second husband especially if the title be named after her. My friend tells me it's not a conjugal property, therefore, we can assign the eldest as the owner of the property inherited by his deceased father. She can also sell the property because it is under her name, is that right Atty? Please help me, I already paid for the survey and the deed of donation is now ongoing. But all of us brothers and sisters are arguing that we should not assign our sister-in-law as the owner of the inherited property.

Your friend already gave you the answer.