I empathise with that completely. But, a child of ours and his or hers grandmother in the Philippines will have great difficulty speaking to one another, if at all. My wife and I have discussed this. My feeling is that if we were to give him or her Tagalog lessons in the UK it simply won't work, I am sorry to say. I have spoken to a few Filipina moms here with children and the children aren't interested in developing their Tagalog here. They are driven by what their mates are doing or not doing and want to speak like them (no fault of their own).
And equally, English lessons for this grandmother is a tall order.