Should choose to see my father after 12 years?

This sounds like a pretty tough situation with no real answers that can be 100% what you should really do. It sounds like you life with your mother is nearing the bottom of the barrel on account of the husband she has, so I think I'd give my dad a try if I was you for your own sake. Has your dad ever tried to contact you? If not, that would then be a red flag that he does not care, and your mother could be right about him, but she seems to have bad taste in men, so who knows.