Simply replace the unfilled areas such as "" and "[date]" with your information.
Dear [teacher's name],
Please be advised that [child's name] will be absent from class for approximately [number of days]. We have had a death in our family, and will be traveling to [location] for the funeral.
I would appreciate it very much if you would gather the work that will be covered during this time. We will make every effort to help [child's name] keep up with his studies while we are traveling, so that he will not be behind when we return.
Thank you so much for your help with this. We really appreciate your understanding in this matter.