How do i housebreak a pomeranian?

Hi,i have a 6month old pom,he was a rescued pup but has nerve damage to his back legs which make it impossible to do stairs,i have to carrry him alot,he falls over and is very nervous of newspaper i guess cause he slips alot .I have been told not to use litter because they could ingest it and become sick.I'm so tired of wiping up pee and poo.HELP!