Hello, I'm Dr. Deb and will do my best to help you today.
I'm sorry that Oliver appears to be constipated although this is actually a fairly commonly seen problem in older cats, especially those who have been diagnosed with kidney issues.
There are several things which can be given to these patients (which I'll list below) but sometimes it's a trial and error process to find the right protocol which works for any one individual.
1. Cat laxatives such as Laxatone or Laxaire which are brand names but every pet or grain store will carry these products. I usually suggest 1-2 inches 2-3 times a day. If a cat isn't too badly constipated, these products work reasonably well.
2, Canned pumpkin (NOT the pie mix) at a dose of 1/4-1/2 tsp per day. You'd be surprised how well many cats like the taste of it
3. Over the counter, human Miralax (polylethylene glycol 3350 aka macrogol 3350) at a dose of 1/8th-1/4th tsp daily which can be increased until soft stools are produced. This is actually a very effective constipation treatment option.
4. Raw bran flakes (wheat bran, not cereal) in canned food 1/4-1/2 tsp daily.
5. For the badly constipated cat, pediatric glycerin suppositories can be quite effective: http://pedia-lax.com/products/liquid-glycerin-suppositories. Read the label closely and only purchase those with glycerin on the label; those with phosphate can kill cats.
If Oliver has been constipated for more than just a few days and/or hasn't been eating or vomiting, then a vet visit may be prudent since these older kidney cats can deteriorate rather quickly.
I hope this helps to provide options for you to consider. Deb