I havea friend who lives in Texas. She rents a 2 story house. Her 3 year old son has become ill and is no longer able to go up and down the stairs. She is trying to get out of her lease to move to a 1 story house. Are there any laws that will help her with this? Her landlord won't let her out of her lease unless she finds a tenent to replace her.

Not really, how long is the lease ? And of course at 3 year of age, she can still carry the child up and down the stairs

Nope, so why isn't she finding a replacement?