Please help me with a young bird?

I found a baby bird on my neighbours lawn, 1 hour later he was still there so we bought him in. My mum then told me to put him back outside so I did, I put him somewhere where I can keep an eye on him. His eyes aren't open properly, he can't walk properly... he sort of waddles and keeps falling over. It is 6.55pm right now, and not many birds are around and no bird is responding to his call. So, what do I do? Shall I keep an eye on him for awhile longer then bring him back in if no bird shows up? I tried the RSPCA but all I got was a recorded message about they are probably learning to fly, but this poor thing can hardly walk let alone fly!!!