I will suggest attractions.
1. you should be in Bangkok for 2 days.
2. the taxi ride to the pier for boat trip to the island 2-3 days.
3. the taxi back to the airport in Bangkok and Phuket for 3-4 days.
4. after that aircraft flying back to Bangkok to return home.
But if you're tired, I recommend you stay in Bangkok a day because I am afraid that your mother might be too tired.