residence nil rate band

I have a man who is close to death who has left his property to his two children and residue to wife.

His property is worth approx. £650 and the residue approx. £80K

Can anyone help me with the wording to ensure that the maximum share in the property goes to the children and residue to the wife. I’m thinking of the value up to the nil rate band to the children. Can I also get the residence nil rate band now for the children ? If so does anyone have the correct wording for this.

Many thanks - sorry its a bit rushed

Collette Hodkinson
CPH Solicitors