Is it valid to perform 'Umrah on behalf of the deceased if the intention for 'Umrah on their behalf was not verbally expressed?

Performing Umrah on behalf of your deceased grandfather is permissible, and its reward will reach him. It is sufficient for you to intend in your heart that it is on his behalf. It does not matter if you do not vocalize "Labbayk Umrah for my grandfather," even though vocalizing the intention is better. Scholars have issued fatwas permitting Umrah on behalf of the deceased or the incapacitated, and that naming the person for whom one performs Hajj or Umrah is better, but the intention alone is sufficient.