Is it permissible to marry a "misyar" marriage without civil documentation and secretly from the husband's family due to his mother's rejection?

"Misyar marriage is valid if it meets the conditions of marriage. Registering it in civil records is an added layer of documentation, not a condition. Concealing the marriage from the husband's family does not invalidate it. It is not permissible for a young man to marry a girl if his mother disapproves, unless he fears falling into sin, and the relationship with the young man must be severed unless his mother agrees. The young man is not obligated to obey his mother in marrying a girl he does not desire."