Was in a similar situation as you. My youngest brother graduated and then sat there all day playing video games and ordering pizza with what little money he got doing jobs for my dad.

Everybody tried talking to him, encouraging him and even at one point my mom threatened to kick him out.

Finally I got sick of everyone pissing and moaning about what to do about him. Figured he was my little brother and I might as well take care of him.

Filled out about ~70 job applications in his name. Most of my family had that oh-so-common "he'll never learn his lesson if you do it for him." I honestly could not care less about teaching him a lesson or showing him the value of blah blah blah. I wanted everyone to shut up about him being a lazy unemployed whatever and to help my little brother.

He's been with the same company for 10+ years now doing quite well. Did he learn a lesson? I suppose that he can always rely on me to have his back. All that matters is to me is that we're both doing fine.

Maybe it won't work for you.