Here is an up to date simple senior computer survival kit which will do it all for a senior.
An easy to use new smartphone at under $100, such as a Republic Moto E or a Windows Blu JR phone, along with a no-contract $10 to $30 monthly plan.
A low-cost Android tablet such as Dell's 7" Venue at $130 or less.
A tablet such as the Acer C720 Chromebook, or Hewlett Packard Chromebook or Windows 8.1 tablet coming in November, all of which are under or just over $200.
If you go with Windows be prepared to learn some new things.
Next spring Windows 10 will restore a more friendly look and function.
Or just go one at a time.