If the mandate goes, the rest of it goes as well. There is no severability clause in the legislation.
The only time a severability clause is required is when Congress wants to specify that a provision is not severable. See the Eleventh Circuit's ruling explaining why they severed the individual mandate:
First, both the Senate and House legislative drafting manuals state that, in light of Supreme Court precedent in favor of severability, severability clauses are unnecessary unless they specifically state that all or some portions of a statute should not be severed. See Office of Legislative Counsel, U.S. Senate, Legislative Drafting Manual, § 131 (Feb. 1997) (providing that a severability clause is unnecessary but distinguishing a nonseverability clause, which provides that if a specific portion of an Act is declared invalid, the whole Act or some portion of the Act shall be invalid); Office of Legislative Counsel, U.S. House of Representatives, House Legislative Counsels Manual on Drafting Style, § 328 (Nov. 1995) (stating that a severability clause is unnecessary unless it provides in detail which related provisions are to fall, and which are not to fall, if a specified key provision is held invalid).