Is it permissible to complete a marriage with a young man who entered into a fake marriage contract to obtain residency, and must he inform his parents of that, and what is the ruling on his previous action given his ignorance of its prohibition, and do any legitimate obligations result from the fake contract?

A sham marriage, not intended for a lasting marital relationship, entails religious prohibitions. If the young man was ignorant of the impermissibility of his action, we hope he bears no sin, for ignorance lifts accountability, as indicated by religious texts. A Muslim must inquire about what they are ignorant of before undertaking an action. If the young man is religious and of good character, accept him as a husband, and disregard the past sham contract. Informing the parents is not a condition for the validity of the marriage, but informing them is better to avoid undesirable consequences.