According to your introduction, this situation is frivolous, which will generally have a spiritual impact on the residents, depending on the individual's attitude towards this matter.
There is an example in Shao Weihua's book Feng Shui. Contrary to the landlord's situation, the solution is:
1. Install thick curtains on windows and doors and put them down at night;
2. Post a gossip by the window, but don't have a mirror.
I hope I can help you.