I hate using him. I hate using him/her. I hate using her. I hate using them, but I'm going to try to get used to it because I think it makes the most sense.
"They/them" is not even a modern usage. It dates from the sixteenth century.
"Immersion in the life of the world, a willingness to be inhabited by and to speak for others, including those beyond the realm of the human, these are the practices not just of the bodhisattva but of the writer." --Jane Hirshfield