We want to remove the letters on his shirt
Set your soft brush with a flow of 70% and paint now on a new layer. Pick up the color around the letters to set your color. To do that hit the Alt key.
By sampling the color many times you slowly remove the letters.
When the letters are gone you gonna make the brush bigger and sets the flow around 30. Now you can easily brush over the area again to let in blend in better.
If you made mistakes just undo it or use the Eraser tool (E)
Easy and fast.