Obligatory "Don't do it" remarks: If the guy isn't trusted enough to even show up to work, and can't get a personal loan directly from a bank (Home Equity Line of Credit would suffice), this is really setting things up for failure. What if he quits? What if you need to fire him (you know, for not showing up for weeks)?
In order to be able to place a lien on his home should he default on the loan, you'll need to draft up a loan agreement or promissory note stating specifically that you have the right to do so. Get a lawyer involved.
Here's an article that talks about setting up a Private Home Loan, which is geared more at helping someone buy a home, but may prove useful in this case as well: https://www.nolo.com/legal-encyclopedia/borrowing-from-family-friends-buy-29649.html
It's pretty lengthy, so I won't quote it out here, but the gist of it is: Get everything in writing in a legally binding contract.