he is a good boy that is friendly

1）he is a good boy that is friendly 这句表达正确.他是一个友好的好孩子.
2）非限制性定语从句只能用who,whom,whose,which,when 和 where来引导不能用that,并且用非限制性定语从句时前应加逗号.
若改成非限制性定语从句则是：he is a good boy ,who is friendly.