why does the author use"have"not"having"here?Thx.
I have everything I need, why
would I move out! Have a great roof over my head,
my mom does my laundry and cooks for me, what
else could a guy ask for!
why does the author use"Have a great roof over my head"not"Having a great roof over my head"here?Thx.

Question

Answer

He's just omitting the subject of the sentence because it's the same as the previous sentence. He could also omit 'have' and that would actually be the more common usage.

Answer

The English used here is very informal :  it should be  'I have a great roof . . '
You could say  ' . . having a great roof . . . my mom doing . . and cooking . . '  but this sounds more formal.