After school I will go home and then I (have) ___ dinner. My mother (have) ___ dinner with me.

1. The first part of the sentence uses 'will go', indicating a future action. The second part describes a subsequent action in the same future context.
2. For 'I (have) dinner', the correct form is 'will have'.
3. For 'My mother (have) dinner', the correct form is 'will have'.

Answer: will have, will have