This is one of the very few times I disagree with Abezon's answer. While his statement (without the parenthesis) is accurate, when the "(death)" is added it creates a whole bunch of problems.
The key is *why* is the money being received? We don't have enough facts for that here. Was it for the potential future wages of the deceased? Was it for the loss of consortium? Was it for pain and suffering? Or, was is just for the direct money damages which resulted from the injury? Each would be treated differently, and only the last would be completely non-taxable.
Since mom was killed and the OP (child) is getting the money, I bet that any money which flows directly to the OP from the insurance company will be taxable. I'd have to check to be sure, but that's my off-the-cuff answer. If it flows through the estate to the OP that is a different story. In either case, we would need to know exactly what the settlement is for in a legal sense. (As opposed to a factual sense as in "mom was killed".)
Error Correction:
My "off-the-cuff" answer was wrong in that it is irrelevant if the person received the money directly from the insurance company or if they recieved it through the estate in regards to the taxability. However, "a taxpayer who is not the injured party in a personal injury lawsuit, who receives a portion of settlement proceeds from the lawsuit as a non-party, is not allowed to exclude the portion received from gross income unless the taxpayer establishes an independent basis for exclusion. It does not follow that because the injured party has a right to exclude settlement proceeds from gross income that a non-party who also receives a portion of the settlement may exclude that portion under Code Section 104(a)(2)." (per Kleinrock's Federal TaxExpert section 18.2)