Is the paternal grandfather's cousin's daughter considered an aunt, if the father is older than his paternal uncle, who was suckled by his paternal aunt along with her daughter?

If your father was not nursed by his paternal aunt, but one of your paternal uncles was nursed by her, then her daughter is not your paternal aunt through suckling and is not unlawful for you, unless she is unlawful to you from another perspective. It is a condition for suckling to be prohibitory that there be five full, satisfying sucklings.