What is too serious to be joked about?

i refrain from disabled jokes i think they dont deserve it as their lives are likely hard enough already. its like theres this guy in my village who had acid thrown in his face and everyday people stare at him and its so horrible. however there is a disabled guy in my college and has a username of "the cripple" on Steam so it depends on the person entirely, he himself doesnt mind and makes them himself because he is content on how his life is and has good mates and everything is fine for him. i cant talk anymore i gtg get the bus to college now so cya :) and sorry if ive come across as a piece of shit...i do that sometimes but hey, my friend greets us with the "alright c***s" phrase everyday so everyone has different senses of humor haha, then again were teenagers so its understandable