@sybbie719 is correct.
So…are you a resident of California or a resident of Colorado?
Both CU Boulder and UCSB are public universities in their states. It is very unlikely that you will see more aid at either school just because there are two students in college at the same time…Unless your FAFSA EFC for each goes below the amount to qualify for a portion of the Pell Grant. What was the EFC for the CU student this year?
If you are a CA resident, the vast majority of need based aid comes via the Calgrant program. Do you qualify for the Calgrant? And any federally funded loans you might qualify for. And the Pell…but really only if your EFC is low for each kid. That’s it.
If you are not a CA resident…forget about any need based aid at all.
If you are a CA resident, this means you are paying OOS costs for your kid to attend CU, right? You said he got a little bit of aid from CU…what was that?
Neither of these colleges guarantee to meet full need for all accepted students.
Honestly, run the net price calculator at both colleges. Do with one student in college…and then with two…and see what you get for results. If you are divorced parents, own a business, are self employed, or own real estate other than your primary residence, the NPC won’t be accurate.