If your friend is on medication then he/she may need to have the meds adjusted. Also I presume they have already seen a doctor to get the script in the first place so that door has already been open.
Getting out in the daylight and walking is a simple way of lifting the spirits as is any form of activity. If your friend finds it hard to get motivated encourage him/her, go with them for the walk. In most cases of depression activation proceeds motivation, so difficult as the first step is it will lead on to the next one and hopfully to feeling better.
RE: FUN DATES WITHOUT BOOZE????
Ah you just dont appreciate good music