They will probably ask you a bunch of questions and hold/play with Sean. Since he is so little, it will likely be more of just asking you questions.
For evaluations/goal settings, I try to always make a list for myself of what my concerns are so that I am prepared.
To qualify for EI (here anyway) your DC had to have a delay of "X" amount or be diagnosed with a condition that is usually associated with delays.
Ours was a lot of paperwork, going over their procedures and plans, asking questions about what he does.
DS was 3 weeks old when they came and they checked to see if he responded to sounds, moved against gravity, tone, etc.
It was only about a 30 minute visit.