If you want to know who is the vocal teacher, she had a web site for vocal lesson at http://www.singaporesingingteacher.com or you can Google Grace Ng Studio. She called it Vocalogy which I think this is not a registered company or organization. If you want to have lesson with her you may be expose to more risk that any issue may happen such as this compare to music school which is a registered organization or company.
I think our medical history is strictly confidential so if we were asked to check with doctor to get certified to fit to attend or continue vocal lessons or more details, this is not really appropriate to ask doctor as normally doctor will not tell you in detail. What the music school does is if the teacher find it not able to teach after a few lessons the school may terminate the student in writing. But I have seen none of the music school really ask student to disclose any medical history before they are accepted or enrolled or in the registration form expect this vocal teacher quite special.