The first is that the theme is not responsive for mobile.

Recreating the look and feel of your old theme using a child theme of a (free) modern, responsive theme like twentysixteen is what I would do…

The third and most important is the errors being output on your single post pages:

Fatal error: Uncaught Error: Call to undefined function related_posts() in /home1/charcoa1/public_html/wp-content/themes/TCPv2/single.php:24 Stack trace: #0 /home1/charcoa1/public_html/wp-includes/template-loader.php(74): include() #1 /home1/charcoa1/public_html/wp-blog-header.php(19): require_once('/home1/charcoa1...') #2 /home1/charcoa1/public_html/index.php(17): require('/home1/charcoa1...') #3 {main} thrown in /home1/charcoa1/public_html/wp-content/themes/TCPv2/single.php on line 24