It can take a while for an older chin to warm up to new people. Since he's laid back, why don't you try placing your arm in the cage and letting him come to you , or if he seems ok with it, when you talk to him with his head poking out of the house, just pet him gently while you talk to him...
My chin lost her left arm on a holiday weekend, so I sympathize. I was able to get her to an er vet, however - I had no choice really as it was a compound fracture and her arm was dangling by a piece of skin.
They did outfit her with an e-collar (one that they cut to fit her specifically) so...
I used to give them small bits of whatever I was eating - carrot, green bean, rice (they loved rice) tomato, strawberry etc.
sweet potato is another favorite - and if they ever have a tooth problem, sweet potato baby food is a big hit!
You can get the large glass containers with lid in walmart for under $20 I believe
I got a large vase from Marshalls for $10 that tapers to a smaller opening, less dust gets out when they roll due to the small opening