Question

Mr.Brown usually get up/gets up... Mr.Brown's wife usually get up / gets up..... Mr.Brown's children usually get up / gets up ....The children's uncle usually get up / gets up ... The children's Grandpa usually get up / gets up...

Answer 1

Gets up, 
Gets up, 
Get up,
Gets up,
Gets up.

Answer 2

Here are the correct forms of the sentences:

1. Mr. Brown usually gets up.
2. Mr. Brown's wife usually gets up.
3. Mr. Brown's children usually get up.
4. The children's uncle usually gets up.
5. The children's Grandpa usually gets up.

In the singular third person (Mr. Brown, Mr. Brown's wife, the children's uncle, and the children's Grandpa), we use "gets up." In the plural third person (Mr. Brown's children), we use "get up."