selective capability disorder

refers to a broad range of pseudo-maladies (where the person is merely faking/exaggerating a certain physical/emotional/mental infirmity/disability, like the infamous “selective deafness”) that many lazy/selfish/uncaring people complain of, merely to get out of performing some undesirable task. these supposed maladies include:
(1) selective stamina/fatigue disorder, whereby the “sufferer” instantly becomes a nearly-lifeless “limp rag” whenever anything resembling w-o-r-k is requested/suggested; he always seems to be perfectly able to jump robustly back up again, though, when some fun/pleasant activity is subsequently offered or suggested
(2) selective phobia disorder, whereby the “sufferer” claims to have an intense fear/loathing of a certain aspect of the task at hand, again, usually to simply be relieved of having to partic-p-te in said task; he often seems to be able to placidly/confidently manage other similar-context activities just fine, however
(3) selective allergy/medical-condition disorder, similar to #2, whereby someone claims to have a serious illness/infirmity that would prevent him from safely performing a less-than-pleasant task, yet he’s perfectly okay with less arduous/boring tasks which involve the same types of substances/conditions
(4) selective strength/health disorder, whereby someone claims to not be physically muscular/fit enough to perform a certain task, but yet he lifts weights, moves heavy loads in a hand-truck/wheelbarrow, etc. at other times
my uncle claims to be helpless.clueless whenever i ask him to step in and help resolve a dispute between a fellow youngster and myself, yet he is a headmaster at a private school and is known for his firm leadership there… sounds like selective capability disorder to me!