I would recommend contacting the heirs of your landlord to determine if they would be willing to release you from the lease that you are under. Health & safety issues such as those that you describe - water coming through the electrics, etc. could potentially be the main reason to request release from your obligation.
Very difficult situation.
I wish you the best of luck. If the heirs are unwilling to work with you it may pay in the long run to retain an attorney.
Your contractual obligation should pass to the heirs or successors of the deceased.
Does your lease contain language containing provisions for also being applicable (or not) to the successors or assigns of one or both parties?
It would look something like this:
"Binding Effect: This lease is binding upon and insures to the benefit of the parties to this lease and their respective heirs, executors, administrators, successors, and permitted assigns."
If there is no such provision in your contract, you may have a void contract.
Do you have anything in writing stating that the repairs/work would be done? If so, that may be ammunition to persuade the heirs to let you out of the lease. If you can legally prove that he was responsible for those things, the heirs will have to ho9nor it.