A mechanics’ lien can be recorded against the property that was improved by the contribution of labor, materials, or both. Proper pre-lien notices must be timely served on the owners of the property to protect the contributor’s lien rights. It is not clear from the question whether the material supplier has lien rights. A call to your legal counsel with all facts should make it possible to provide an accurate response.
No you can’t. Please contact me to discuss a lawsuit to collect the debt. If there was fraud you could try and pierce the corporate veil and go after him personally.