as per your query, if any person who is married, his wife is considered as a nominee, but she got remarriage then she is not entitle for getting the gratuity amount in this case parents are legal nominee.
Share of gratuity is mention in the form which has been filled by the concern employee at the time of joining.
% of share is also mention in this form.if nominee is one person then he/she will be entitle for 100% gratuity and if two are then equal portion will be given.