How can my dad continue getting paid if he's hurt on the job?

my dad is currently staying at home recovering from chemotherapy or because of it. he won't be going to work at his job for quite a while but until then when he is able to feel better enough to start working again, how will he be getting his money for now? my dad works as a federal employee and he does receive a lot of benefits including health insurance. is there some form he can fill out to apply/qualify for this?