I see three choices...
1) You can accept the requirements as "passed" and note for the parent and the Scout that "A Scout is Trustworthy" . I have often found that if the Scout says he passed the requirement, then he has passed the requirement. If not, ask him would he like to pass it NOW ?
2) Suggest, if in your judgement (as Webelos DL, yes?) the Scout has not quite fulfilled the requirements as listed (age, skill, attendance, etc.), do not sign off. While addressing THE SCOUT (!) not the parent, (because it is the Scout who must pass the requirements, yes?) ask about the di