Did Nala have a little brother name Mheetu?

I dont think so, but dont quote me on that cuz I haven't read any of the books, just watched the movies.

No, she does not. The 1995 Laserdisc release of the movie reveals that a little brother to Nala was intended but cut out in early production, long before the movie script was even that what we see in the movie. As in Nala has never had a little brother in the story that is the movies.

All official books and comics are only profit fanfiction weitten by outsiders and ignored & contradicted by Disney in relation to the movie universe storyline, so the books and comics do not matter to anything in the movies. But for all I know Mheetu has never been taken into any books or comics either. He exsists only in unofficial fanfiction.

no

I don't think so. Nala is Sarafina's only child.
and I never herd of him.

Yes

Yes. because Disney had him cut out. But Mheetu did exist. Also let's say Mheetu's dad was a killed/exiled lion meaning Mheetu was Killed/Exiled by Scar or Mufasa.

She did. But not anymore. Mheetu is now non existent because he was cut out by Disney.

Yes but Scar killed Mheetu a long time ago

Yes she did. But he died when they were young. In a lion king comic it actually shows him.