In general they do not help comfort, certainly not at the end-of-life and sometimes not even in general terms. If the goal of the person and their family is comfort only and the last few weeks of life is approaching, then using antibiotics for any infection will not help them to be more comfortable.
Pain killers (such as morphine or hydromorphone), breathing treatments, muscle relaxants (such as lorazepam), will help someone to rest more comfortably. By feeling more comfortable and sleeping better, they may actually improve with just that; or may continue in the dying process.
If someone is not nearing death, the discomfort related to some infections such as in the bladder, can be relieved more quickly by taking an antibiotic.