Question: When did the peeing problem start?

Following is a mixed bag of suggestions and thoughts.

Call the Humane Society and talk to them. They are reacting to the child, I am sure. Maybe they or a friend could foster them for a while.

Nancy Efrusy is a pet psychic that has done wonders for people here. She is in the USA, and very reasonable. [email protected]

At the very point where the cats need extra love and reassurance, they are behaving in a way that doesn't get them that.

Feliway is a relaxant for cats; it's expensive though a little lasts a long time.

Again - I think they have to have their own safe child-proof place. Basement?

Making them outdoor cats could result in an expensive vet visit -they are 10, and not accustomed to the outdoors. All you need is for one or both of them to be hit by a car or hurt by an animal, and to survive...and the vet costs associated with surgery or euthanasia.

The boy is only permitted to interact with the cats when supervised. He is a bit rough with them and parents stop him right away.
DON'T allow the youngster to interact with them at all. Question - how do you keep them apart when he is not supervised? If that works, do it constantly.

Otherwise - rehome them as a pair. Safest and best for them...especially if vet checkups are going to be a problem for a while.