Had to break lease to move in-laws in with us due to medical conditions, are there exemptions in the law allowing this?

Not sure what you mean by break lease but if you mean adding more people to the household, which the lease disallows, you could seek an amendment to the lease to add them to the lease if the landlord approves.  If the lease is such that it includes utilities, perhaps increasing the rent to accommodate two additional individuals may help keep you in the same apartment.

If this is not the situation, a breach of lease is a contractual breach.  The landlord is not responsible for your underlying causes for the breach, so if you had to move, you are responsible for the rent until such time as the apartment is rented until the end of your lease.  The landlord must mitigate his damages by using reasonable methods to re-lease the apartment.