Here are some suggestions from a neighbor who has had this problem in the past:
If he thinks the neighbor is reasonable, then I would send a typewritten note politely explaining that he has tried to make personal contact to discuss but unsuccessfully. Then, define the problem…excess barking of the dogs. He needs to provide a list of the dates and times that the dogs bark non-stop to show unreasonable noise. For example, if the dogs bark continuously from 5:30 p.m. through to midnight…..then sporadically throughout the night waking him up…. That would be unreasonable. However, if the dogs bark from 9:00 a.m. to 1:00 p.m., then stop until 5:30pm to 8:00 pm, that’s not unreasonable. Anyway, that also provides documentation if further action is necessary. He could request that the owners of the dogs keep them inside after 10:00 at night so that all can get some sleep. (that worked for us with a neighbor whose dog barked continuously all night long. The neighbor complied). Leave a phone number so that the neighbor can contact him if they choose. Responsible people will.
If that doesn’t work, then he should check for the owner of the property through Dallas CAD (www.dallascad.org). If the owner is NOT the neighbor, then, he should send a certified letter (shows proof of delivery or attempted delivery) to the owner of the property notating a problem with his tenant. Owners are responsible for the behavior of their tenants. If the neighbor IS the owner, then address the certified letter to them, again requesting that they deal with the barking dog issue. If that doesn’t work, call the police and be prepared to file a complaint for violating the noise ordinance. That will get ugly, of course. He can also bypass the letters to the neighbor and/or owner and call the police, but the police will have a better chance of dealing with the problem if he follows steps 1 and 2 above. Above all, he should always be polite and calm with whomever he deals with.