Hey there,
I noticed that you have applied the following CSS code for the related post area at Theme > Custom CSS:
#eb .eb-entry-related >div:nth-child (1n+2) {
    clear: left;
    border: 1px solid #e1e1e1;
    border-radius: 0 0 3px 3px;
    padding: 15px;
}
#eb .eb-entry-related>div {
    float: left;
    padding: 15px;
    width: 30%;
    margin: 5px;
    border: 1px solid #e1e1e1;
    border-radius: 0 0 3px 3px;   
}
In order to show 2 x 2 view for the related post area, I suggest you to use the following CSS code to replace the old CSS code: 
body #eb .eb-entry-related > div:nth-child(3n + 1) {
    clear: none;
    border: 1px solid #e1e1e1;
    border-radius: 0 0 3px 3px;
    padding: 15px;
}
body #eb .eb-entry-related > div {
    width: 48%;
    margin: 5px;
    border: 1px solid #e1e1e1;
    border-radius: 0 0 3px 3px; 
    height:350px; 
    float: left;
    padding: 15px;
}
Can you have a try and see how it goes? 
Do take note that clear all your cache before you see the changes.