If it is a normal lease, generally, your lease is terminated, simply because when one party to the contract falls away the other party is released from the obligation. The owner can take possession of the property again, unless a succession clause has been included in the lease agreement. In this case the owner, as the contract party, must under the conditions of the lease transfer the lease rights to the heirs of the lessee. Some insecurity remains when the owner does not want to cooperate with the assignment and registration of the lease to the heirs (he does not like the new lessees or has reasons to want his property back), or when you are not dealing with the original owner this option may not be enforceable by legal action at all.
The subject of succession and inheritance of a lease is not straightforward in Thailand.