Then I go back/come back home and help my brother with his presentation.

[Tony_M]

Hello.

A: Are you busy tomorrow?
B: I'm afraid, yes. I've got quite a few things to do at home. I've got a dental appointment at 2 pm. Then I go back/come back home and help my brother with his presentation.

Source: my dialogue.

Should I use "come back" because initially I will be at home? Or should I use "go back" because I imagine myself from the perspective of being at the dental clinic at 2:40 or 3:00 pm when I need to return home?

Thank you.

 

[jutfrank]

You simply have to think about where you are when you say it. If you're at home when you say it, use 'come'. Otherwise, use 'go'.

Also, you don't ideally want to use the present simple in that clause—there are better options.

 

[emsr2d2]

Source: I wrote my the following dialogue. (This should be at the beginning.)

A: Are you busy tomorrow?
B: I'm afraid so. , yes. I've got quite a few things to do at home. I've got a dental appointment at 2pm. Then I will go back/come back home and help my brother with his presentation.

Should I use "come back" because initially I will be at home no question mark here or should I use "go back" because I imagine myself from the perspective of being at the dental clinic at 2:40 or 3:00 pm when I need to return home?

Note my corrections above. With "I'm afraid", we generally follow it with "so", "not" or "person + verb".

To express "Yes" to A's question, say either "I'm afraid so" or "I'm afraid I am". Obviously, if you're not busy, say "No". The "I'm afraid" acts as a sort of apology or expression of regret.

"I'm afraid not" would be a response to something like "Are you free tomorrow?"

 

[Tony_M]

Note my corrections above. With "I'm afraid", we generally follow it with "so", "not" or "person + verb".

To express "Yes" to A's question, say either "I'm afraid so" or "I'm afraid I am". Obviously, if you're not busy, say "No". The "I'm afraid" acts as a sort of apology or expression of regret.

"I'm afraid not" would be a response to something like "Are you free tomorrow?"

Thank you, @emsr2d2.

Can I use the present continuous or "be going to" instead of the future simple? The activities in my dialogue are planned and prepared.

 

[emsr2d2]

Thank you, @emsr2d2.

Can I use the present continuous or "be going to" instead of the future simple? The activities in my dialogue are planned and prepared.

I assume you're talking about the part in which I added "will". (In future, please quote the relevant part of the post you're referring to.)

I suppose you could say "... then I'll be going back home to help my brother ...".
I was actually just looking back at my corrections when I saw your post, and realised that I wished I had changed it to "... then I need to go back home to help my brother ...".