First, yes, he "lives there", apparently under an agreement with you, making him legally a "tenant" and you his "landlord". Your landlord may be displeased by this.
Second, yes, the general rule in our society is that someone causing damage anywhere is "responsible" for paying to repair it, even if he's just a visitor, let alone a resident or tenant.
Third, as your tenant, he would have the ordinary obligations of any other tenant to pay rent and to give you adequate notice prior to moving out, etc.
Finally, you can almost certainly be evicted (by YOUR landlord) if you have violated the lease or state law by not properly notifying your landlord of the additional resident. Or you can negotiate something else, such as paying a higher rent for a year...
Bottom line, we don't really know, we're not your lawyers and you can only get legal advice from your own lawyer in SC.
Of course not. It's up to you to inform
USPS
He has established residency. However since the LL did not know he was there, you have subjected yourself to eviction for a lease violation.
And since he was not on the lease, you are fully responsible to your LL for the rent and any damage done to the unit (regardless who caused the damage). You could try to sue him for the damages he caused to the unit, but there is no guarantee that you would win the case. And even if you did win, you probably won't ever see the money.
Not a tenant, but he has established residency.
In order for hi to be liable for any rent, etc, you have to have an agreement with him. Being a resident doesn't automatically make him liable.
" Does that make him a legal resident" absolutely not.
"and if so does that make him liable (to me anyway) for part of the rent/utilities and any damages that he did?" if he was a tenant then he'd be on the lease agreement and held equally responisble as you are to the landlord and not to you (as sub-leasing is prohibited in nearly all standard Lease contracts).
No.
If you didn't tell the landlord, and didn't get your friend registered on the lease, then YOU are still the tenant, and YOU are responsible for his "rent" (not really rent - you had an informal arrangement with him, not legally binding) and for any damage caused by him or by yourself.
no, it doesn't
if he was not on the lease, he is not a tenant, he is a visitor
and, your landlord may have some time restrictions for 'guests'
if he caused any damages the costs to repair are YOURS
I live in South Carolina and my old roommate (who lived with me but was not actually on the lease - I let him move in without telling the landlord) started getting his mail sent there. Does that make him a legal resident, and if so does that make him liable (to me anyway) for part of the rent/utilities and any damages that he did?