Do you mean what should you put in the gender field? I'd put their gender as they currently identify, so in this case female. Everything else flows from there: if the profile says female, it will say daughter, sister, wife, mother, etc.
Alternatively, you could leave the gender field blank, and gender neutral words will be used.
I don't know if this person is out as a transwoman, but if you're going to mention that in the bio be sure to check the privacy setting. You don't want to accidentally out someone on the internet!
I hope that helps.