Urgent advice needed!

Help! A fledgeling pigeon landed in a friend's balcony and we don't know what we should do. My friend lives at the second floor in an apartment block and the baby pigeon's nest is set very close to her balcony, but it can't be reached by any means, so she can't place the pigeon back into the nest. This being said, what's best for the pigeon? Should she leave the baby in the balcony so that the pigeon parent can see/hear him and come feed him? We don't know if this baby can feed himself, maybe someone here can look at the picture and tell us if he's old enough to feed himself? He refuses to open his beak to be handfed.
At night the temperature drops at about 2 degrees Celsius. I can see that he has a complete feathering, but do you think he could manage to warm himself up at this temperature?
Is it better for him to be kept indoors at this age?

That's him here: https://2img.net/h/oi41.tinypic.com/zy671s.jpg

Hi Matroshk,

He looks about 3-4 weeks old and probably doesn't know how to feed himself yet, neither would he manage to keep himself warm. What part of the world are you in, maybe there is a member near you who could help.
Sorry about the delay in replying, I have been offline since Friday, just got back. If you can, please post on the Pigeon Angels Facebook page, that's where all the members hang out nowadays:

https://www.facebook.com/groups/176239232007/

I hope you have managed to get help meanwhile and the baby is doing OK.

We decided to let the baby stay in the balcony and my friend placed a heating pad under him during the night. He was eating by himself, a little clumsy at first but after a couple attempts he learned how his beak works. He remained in the balcony about a week and one morning he wasn't there anymore :)

Thank you so much for the update, Matroshk!  
It's great to know that you were able to help the baby stay warm, safe and fed until he was big enough to start living his life independently.
Wonderful job!