I agree, a vet visit is the only away to know for sure what is wrong with the leg. From your description it doesn't sound like something related to impaction, but could be related to a break or dislocation of the leg/hip joint.
Without a full background on the dragon, I can't even guess what could be the problem. If this started very suddenly, then definitely a break/dislocate is likely, especially if the dragon fell or had something fall on it recently, or was rough handled. Or became trapped under cage furniture and fought its way out and injured itself in the process.
Definitely tell your friend he needs to take his dragon to a vet for examination and treatment. If he refuses, then he's being neglectful and breaking the law (animal cruelty laws may not be severe, but its the responsibility of all owners to ensure proper medical treatment is sought for injured or sick pets, irregardless of what species. If your friend can't afford to take the animal to a vet, then he should surrender it to a rescue or shelter, or to somebody willing to pay for any necessary treatment. Or at the very least, have the animal humanely euthanize.)
-----
PHLdyPayne
Forum Princess