Found a pigeon in my elderly mums garden. What to do?

Yesterday we found an injured, bloodied pigeon sheltering by mums conservatory. I approached it and at the very last second it flew off. Next door neighbour suspected it was her cat who had caused its injuries as she had seen it prowling. 

Today while visiting again we saw another pigeon in the exact same place but no visible injuries this time. I approached it with a towel and it made a feeble attempt to move but I was able to catch it easily. It has a ring on its leg and seemed ok with being handled was quite calm. I brought it home with me as I wasn't sure it was safe with the cat next door being out and about. 

It is safe in a box now and has had a drink of water but doesn't seem interested in the bird seed as yet.

I have the details from the leg ring.

Red ring reads GB 22D 92765

Blue ring reads 07398 402285.

Any advice please?