From what I've read, a repo man can enter your house with permission from the person inside the house. However, he/she is not allowed to damage your property in the process of repossession. You should consult a lawyer for professional advice.
He can if your mother in law let him in. But he can't cut your locks. But sense it is done and over with might as well let it go and figure how your going to get the item repo'd back. Out here in Arizona repo guys got this thing now. If they know the item is in the house or garage that is getting repo'd they call the police. The police come over and make you open the garage so the repo man can get what he came for.
No one is allowed into your home unless they are invited in or have a court order. special circumstances are only if some-ones life or property are in imminent danger eg. fire, explosion, flood,etc. As far as cutting your locks The only way he can legally cut your locks is if he is told to by the police or fire depts. period! Otherwise it is crimminal damage to property and he or she can be arrested.