attend on someone—
1. act as a servant; carry out smb.’s wishes:
- A king would have as many as one hundred people attending on him.
2. give personal help to smb. (as a nurse, doctor, etc.):
- Jane has been attending on her sick mother for years.
attend to someone—
1. give one’s attention to smb.:
- Attend to me, children, I shan’t repeat these instructions.
2. = attend on someone 2:
- She was attending to her sick grandmother when her father came to the door.