Question

1. He is at table.
2. He is eating.
3. He is sitting at the table.
[Does #1 mean #2 or #3?]

4. He is at the table.
5. He is eating.
6. He is sitting at the table.
[Does #4 mean #5 or #6?]

Answer 1

1 is not good English. 2 and 3 are phrased well.
Neither 1 nor 2 means the same as 3.

4 and 6 mean the same thing. 5 is close, but not exactly the same.