The best help often comes from the people closest to the situation. Your child's teacher, principal, school counselor or a family liaison may be able to help. You can also ask to connect with the district's attendance person. You can find information online from the Washington state Office of Superintendent of Public Instruction (OSPI): https://www.k12.wa.us/student-success/support-programs/attendance-chronic-absenteeism-and-truancy/attendance-resources-parents-guardians.
If your child receives special education services or accommodations – or you think they should – try connecting with your principal, special education teacher, or your district's special education office. Read more about accessing services for students with disabilities in OEO's Parent Guide for Protecting the Educational Rights of Students with Disabilities. There are also organizations that connect Parents to Parents to support families with kids with disabilities. You can find contact information for parent to parent programs here: http://arcwa.org/getsupport/parent_to_parent_p2p_programs.
There is help for students who are homeless, and students in foster care. You can start looking for information by calling your school or checking out OSPI's website, here: https://www.k12.wa.us/student-success/access-opportunity-education/homeless-education and here: https://www.k12.wa.us/student-success/access-opportunity-education/foster-care.