For the record, crab- mentality doesn't apply to the Filipinos only. It applies to anyone who exhibits such attitude. Crab - mentality is only a term to define the above-mentioned details. It was brought about by the spaniards through colonialism and passed it over through generations.
As for your additional question, I can relate to what your telling. In general sense, he is indeed guilty of being a "crab - mental" by putting his heritage down. He is like wanting to be someone he cannot at the expense of where he came from, which is his Filipino lineage. Aside from being crab - mental, what he really is a pretentious person. Why make being a Filipino a reason, when he who really has a problem. This only shows that he doesn't love himself. He cannot deny the fact he is a Filipino. If he hate it so much, he cannot do anything about it. Instead, he should focus his energy in accepting it in himself that he is a Filipino and being proud of where he came from. As a result, he'll come to love himself and he'll be accepted by everyone without any prejudice, with his head held-up high. ;)