Is it permissible to write an unrecorded marriage contract, without witnesses, for a single Muslim woman (a widow) who is twelve years older than the young man (who is married), in order to avoid haram between them given the work and life circumstances that necessitate their continuous presence together, and the woman's need for care and assistance?

Congratulate the woman on the blessing of Islam and supplicate for her healing. Thank the man for his concern for her.

It is not permissible to be in seclusion with her or to uncover any part of her body, because she is a non-mahram (definition) to him.

He must marry her with a valid Islamic contract that fulfills the conditions of a sound marriage: the صيغة (offer and acceptance), the permission of her guardian (a Muslim or the judge/community of Muslims), and the presence of two just witnesses.

If marriage is not possible, then seclusion is not permissible. She can be helped through legitimate means, such as hiring a maid or having Muslims assist her.