I'm not sure why your realtor would feel it is a bad idea. If that is what you are willing to do then you are still a qualified buyer. The only reason I could see is that when you go to submit an offer, it would be less desirable to the seller as they will pocket less money and could need to do more work to meet FHA requirements on the property. What is important is that you finance what you are comfortable with.... more
I'm not a lawyer, so this isn't legal advice. But, first, read the lease and see if there are any provisions in there in the event the apartment is, or becomes, inaccesssible or uninhabitable. The lease itself may specify something, such as prorated rent for the month(s) in which that occurs.
Second, if the lease is silent on that, first find out what the law provides. Then, armed with that information, either: (1) try negotiating with the landlord, or (2) have your lawyer conduct the negotiations. Unfortunately, at several hundred dollars an hour, you'd probably end up paying a lawyer more than you'd save via a successful negotiation. Nevertheless, those are some of your options.