Hypospadius?

Hello my son recently had a hypospadius fistula repair(2nd surgery) he's nearly 2 and VERY strong. Recently his catheter makes it IMPOSSIBLE to double diaper so now its just one because drs said not to risk pulling catheter for double diaper. But now toddler keeps trying to scratch(I suspect) through his clothes at his penis and catheter. He doesn't let me touch it or even attempt to clean or wipe his penis every diaper change it takes 2-3 people hold him down. What should I do? I'm worried get infected