The question I would ask is this: what is the law regarding joint ownership of bonds? Does it mean that your child and your mom each own half? Or does it mean that they both own the full amount jointly? This is a question for a lawyer.
Also, I understand your question, and, no, colleges will not view the bonds as simply money to pay your EFC that you would have had if you excluded the bonds. It now is money you have available to pay for college, and it will be counted.
BTW, do you mean savings bonds that are in a safe dep box? Or investment bonds?