Umrah with Father's Foster-Father

Question:
Am I allowed to go to umrah with my father's foster father who looked
after my father for many year from the age of 13 onwards, is this man
a mahram to me? I would sincerely like to know if Ican because I need
to make arrangements for me to go to umrah with him and his wife.
Answer:
In the name of Allah, Most Compassionate, Most Merciful,
Your father's foster father, i.e. the man who looked after your father
from the age of 13, is not considered a Mahram to you; hence it will
not be permitted to travel for Umrah with him, unless you are
accompanied by a Mahram.
The reason being is that being a Mahram is established through the
relationship of lineage (qarabah), breastfeeding (radha'ah) and
marriage (musaharah). As such, this person looking after your father
when your father was young does not make him a Mahram to you.
And Allah knows best