Since she is a minor, is that something that I should inform H?
I would say yes.
Be simple and matter of fact - avoid any wordiness. A simple email or text message.
D13 is struggling with issues at home and has requested some support. Made appt at X on this date and time.
Do not hide appts. Do not deliberately schedule appt your H cannot attend unless he states he will not be there. Never do anything that prevents H from being involved.
On the other hand don't expect him to be there. Its his choice. But, don't make it where he can blame you later that he wasn't. Answer any questions briefly and as clinically as possible.