This is difficult to answer without knowing more. Once a person is arrested on a felony, they must be arraigned (told their charges) "without necessary delay" (Cal. Penal Code section 976.) This typically means the person is arraigned within two court days. Now, this time could be effected if the charges stem from a different county or state. The bail itself could change based on (1) the charges alleged; (2) his probation status or (3) if there are any other types of "holds" on him (like immigration or parole.) Your boyfriend should be told by the Sheriff's the basis for why they are holding him in custody.