Hello Deedrio, I am new to this community but I was an educator in America's public education system for several years and I want to make it clear that while the situation is different on a few notes, perhaps I can help you in the handling of parents and perhaps with building a child's interest, even if it doesn't work out. The experience can perhaps help you shape future encounters.
Let's begin with the parents. First, you have to make it abundantly clear to the parents that while you are willing to hear their proposal. Forcing a child to do anything, even if it is for their future is detrimental to not only their child's future in of itself, but to them as well.
If a child has no interest in the language, then perhaps there is a chance to overlap their personal interests with that of the topic. Forcing the child to be there will only make them resent the language and the possibilities it will bring.
I taught in the inner-city schools and the first issue I encountered with a child in the topic of learning was relevance. If the child you attempting to teach sees a subject they have no interest in, that will be difficult because it is not relevant in the mind of a child. For example I had a little girl who was latina, and she didn't relate to the subject I was teaching in Spanish because she had no idea what it was like to go to the beach. The girl was from mexico and could not relate to her own language based off of her experiences, she was in 2nd grade. Another was an 8th grade who didn't want to learn math because she thought she had no future with the subject. Had to teach her about buying more with less in more than a few sessions.
My advice to you is to speak with the parent, ask them what the child enjoys and perhaps try to find a way to overlap what this child enjoys in their personal time such as a hobby or an interest. How I taught a few of my kiddos is that I asked them on the first day, what they enjoyed. And each week, we had a day to incorporate it.