Is it permissible to work with the wife's relatives in their home country, knowing that their work involves paying bribes to obtain bids and tenders, and is it sufficient to waive the share of profits gained through bribes and donate it to charitable organizations?

Forbidden bribery is that which aims to invalidate a truth or establish a falsehood, and it is forbidden for both the recipient and the giver. However, if it is for obtaining a legitimate right that cannot be obtained otherwise, then it is forbidden for the recipient but not for the giver. If the wife's family is paying forbidden bribes, then they must be advised and warned of its sinfulness. If they do not respond, then there is no sin upon you in working with them, as long as your work is not related to bribery, and it is sufficient for you to work as an engineer without their involvement. It is advisable to avoid this work if possible.