[Rue]

...oh wow! Doesn't sound like his owner researched proper care does it?

I guess you have to ask yourself how much you're willing to invest in the bird and take it from there.

How long will his owner be away? Would the owner be willing to give the bird to you if you found you bonded with him?

In this instance a vet visit would be in order so you know what you're dealing with - if's he healthy or if there are issues with his health.

Then you need to get him on a good diet. A good diet for the average bird would consist of appropriate, non-coloured pellets, fruits, veggies, bird-appropriate table scraps (including some lean meats)...and some seed, the kind and amount depending on the bird...

He'd also need regular baths - in the shower, in the sink, a bowl or being misted all work (ex. I shower with my 2 larger parrots, mist the 'tiels, and the budgies bathe in a bowl). Regular can mean anything from daily-weekly - but shouldn't be less than weekly. I find, weather depending, I can comfortably to manage to get in about 2 baths per week per bird - and their feathers look great.

He also needs toys to shred, chew, destroy or otherwise play with. They don't need to be expensive - just made of safe products. Milk jug caps are fun, old pens without the ink refills, most cardboards should be okay, brown paper bags, junk mail (non-coloured, non-glossy)...

Finally, he needs supervised 'out' of cage times, and some road trips would be great as well. While out he needs to be played with and stimulated and needs to get exercise (flapping is great for clipped birds, climbing, swinging, walks on the floor if it's safe).

And of course, lots of cuddling if he's cuddly...if not, he'll need other quality one-one time...