Having or not having Medicaid has no effect on whether your boyfriend can claim you as a dependent or not. He can claim you as a dependent if in addition to being a citizen of the US or a resident of the US, Canada or Mexico:
he provides more than 1/2 of their support,
you earn less than $3,900 in gross income subject to tax (social security doesn't count).
you don't file a joint return with another
you live with your boyfriend all 365 days of the year
