Some colleges use only the parent you live with (custodial parent) for financial aid. Others use both parents. Many of the better-financial-aid colleges (including Rice University) use both parents’ finances.
This means that, for the colleges that require both parents’ finances, both must cooperate with financial aid forms, and both of their income and assets will be used. Also, when using the net price calculator at a college that requires both parents’ finances, include both of their income and assets when filling it in to avoid getting an overly optimistic estimate.