sure it is...

here the court system sometimes orders the perpetrators of crimes to pay for their victims therapy...

another situation ...a friend who doesnt have mental health insurance and need mental health care may ask a friend for help or another friend sometimes offers to pay for them...I have on more than one occasion paid for a friends therapy session when they needed financial help. and sometimes my friends or church pitches in when I need their help..

many parents pay for their childrens therapy even after the child is an adult...my parents helped to pay for my medical and mental health care when I could not afford it myself.

there are many different reasons why one person would pay for another persons therapy..there is nothing illegal, unethical or wrong with someone paying for someone elses health care treatments whether its medical or mental health.