If a Muslim sees something admirable belonging to someone's children, but has not seen their parents or guardian, or if they admire something belonging to a deceased person, such as their picture or one of their possessions, then for whom should they invoke blessings?

The supplication for blessing (Du'a al-Barakah) is for something one admires, and it does not require its presence or hearing, for the evil eye is real. If any of you sees something admirable in himself, his wealth, or his brother, he should supplicate for blessing for it. Therefore, if one sees someone's children or something from his own wealth or the wealth of others, he should supplicate for blessing for it. As for the deceased, it is more appropriate to supplicate for mercy for them.