Not at all. I genuinely believe that older languages can be a hindrance. Look at the Isle of Man. It dropped Manx, essentially over a hundred years ago. It explains why in the Life In The UK Test Supplement. My wife's sister's both learned English to a very high level and both landed good jobs in the Philippines because of it. My wife's nephew learns English at school and is taught in English. His parents recognise that for the sake of his future he needs to make the english language a priority. And of course the business world in the Philippines all revolves around English. Difficult to get a professional job if you can't speak english to a significant degree. All of my wife's families employer's family speak excellent English and do so for a reason i.e. because it is the means of choice to communicate outside of the Philippines, amongst other things.
In Andy's stepchild's case, she has obviously become accustomed to speaking and learning English. And is possibly distraught at the idea of reverting to Tagalog and I can understand that. In some ways, learning Tagalog for her is a retrograde step especially if she is going to be spending the rest of her life in the UK. Better to focus on what she is comfortable with and other, perhaps more beneficial subjects.
I understand why people want to preserve their heritage and their own languages but it can be disadvantageous to do that. There is definitely two sides to the debate.
And I have no doubt in my mind that any child of ours will not be speaking any Tagalog. The child won't want to and that will be the dominant factor.