J.S.
I am a HUGE advocate of sleep training. I would let your neighbour know that you are going to start. Explain that it may be a rough week, but in the long run it'll be worth it for you and her, and your baby. If children don't learn to fall asleep by themselves, this could go on for the next 4+ years!
I have some friends that didn't do it either because they live on the top floor of their hotel. Now they've just thrown in the towel and sleep in their children's room! 4 of them all together! Completely nuts! There 4 1/2 yr old and 2 yr old still wake up in the night and have to be cuddled to sleep.
I have to say there is nothing I have done better than sleep training my 2. It WASN'T easy! Be prepared for lots of crying. You will hate yourself and feel guilty. I started when mine was 8 months because he started waking up more and more until it was 5 times a night and he wanted the boob. They don't need the boob! They have the ability at that age to sleep through the night if they have a good meal before bedtime. Mine cried 2 1/2 hours the first night. I closed the doors between us, openned the windows to mask the cries and turned the tv on full volume. If you listen to them you die. The next night he didn't cry at all!
There are many ways to do it. Choose what's right for you and your child. With my 1st, I fed and when he was almost asleep, pulled out the boob and put in a soother and put him into his own bed. If he cried, I'd do it again, boob, pull out, bed, until they are so exhausted they don't complain anymore. The important part is that they fall asleep without it on their own. (better if you don't use a soother, but with my 1st I had too. Eventually you have to rid them of that too)
Hope you have the courage to give it a try! Your neighbour will only hate you for a few days!