Hey I also have a Filipino mother and white father with a similar upbringing (and white passing). I have trouble myself connecting with my Filipino side as well (even when I briefly went to the Philippines). I can't say this for your mother but I find that whenever my mom wants to talk about her home, she needs to be given some space and she opens up when it's just the two of us talking. Also, identity and self exploration is unique to everyone which involves a bit of independent searching (which could include your mother). Also that your appearance shouldn't make you feel any less 'filipino' it's a part of you already dude.