What word describes someone who never acts thoughtful but blames others for not being thoughtful
If you mean that he does the opposite of what he says maybe you can use hypocrite.
As suggested in the comments by Hellion and Stannius, this Collins definition that I had included can be seen as too broad, so I am including another definition.
According to Merriam-Webster:
2) a person who acts in contradiction to his or her stated beliefs or feelings
If you want to refer to someone who does not think before acting you can use thoughtless Collins:
adjective
1) inconsiderate ⇒ "a thoughtless remark"
2) having or showing lack of thought ⇒ "a thoughtless essay"
3) unable to think; not having the power of thought
or reckless Collins:
adjective
1) having or showing no regard for danger or consequences; heedless; rash
This person is "self-centered":
adjective
concerned solely or chiefly with one's own interests, welfare, etc.; engrossed in self; selfish; egotistical.
independent, self-sufficient.
centered in oneself or itself.
www.dictionary.com
You could say that such a person is:
self-involved: wrapped up in oneself or one’s own thoughts.
Or,
self-serving: having concern for one’s own welfare and interests before those of others