Part-time Nanny Fr o3 Kids, Long-term Option

We are looking for someone reliable and trustworthy to help care for our three kids around 4 days/week. We'd prefer to hire someone consistent, who could make at least a year long commitment. Dad's firefighter work schedule rotates, so the days he has off are not always the same each week. We do know his schedule for the year, but overtime days are not known until one week in advance. Mom starts law school in August (Mon-Fridays, but will also need to study on weekends). On the days Dad works, we are looking for someone to pick the kids up from school and be with them until around 830 p.m. Ideally, we want someone warm and caring who could help with homework and prepare basic dinners. Our two girls are pretty independent, so most of the "babysitting" would be for our 4y/o boy. Weekend days would be different hours (morning-early evening).