A Muslim is a follower of the religion of Islam. Muslim is not an ethnicity, it is not a race, neither is it an indigenous person. So can a person be half muslim? Your father may be Muslim (filipino) and your mother a catholic (irish) but that does not make you half and half of a religion. You are for sure a filipino-irish but not a Muslim-Catholic. If you claim yourself to be muslim-catholic, you are one confused individual.
In conclusion there is no such thing as half muslim or half christian or any half of any follower of any religions. You are either a follower of a religion or you are not. So you are either a Catholic, a Muslim, a Jew but never half of any follower of any religion.
Don't be a confused individual. Follow one religion. If you do not like it, change.
The Muslims coined the term "half-muslim" because they wanted to convince the world that "muslim" is a race.