While in general a voluntary assumption of risk by the plaintiff will defeat the plaintiff's claim, there is an exception known as the rescue doctrine that Texas and a number of other states apply in the situation where a good Samaritan comes along, sees an imminent danger to life or property, and is injured while trying to save the persons/property that are in danger. In that circumstance, the rescuer may indeed have a claim against the negligent person that created the danger in the first place even though the rescuer knows that doing so is a risk. Holding otherwise would discourage people from trying to rescue others and thus would not be consistent with public policy.
Texas, as do most other jurisdictions, vary from the accepted standard(s) from time to time.
There have been exceptions, however, I humbly suggest our OP to discuss what legal remedies might be available by meeting with three or four personal injury attorneys.
Texas' "rescue doctrine" creates an additional duty for a defendant who creates a dangerous situation.
It says that the defendant is legally responsible to anyone who gets injured while trying to rescue the defendant, or another person, from the dangerous situation which the defendant created.
Based upon what the OP has revealed about the night under discussion, I don't know enough to presume that the fire was caused by the homeowner/occupant.
The OP has revealed that a fire was observed by the OP, the OP began to rouse the occupant(s),
and tried to fight the fire.
There is a 1948 Texas case Longacre v. Reddick, in which a truck driver's negligence caused a truck filled with gas to crash from which a fire ensued.
When the plaintiff tried to rescue the driver from the burning truck, he was injured when the truck exploded.
The court decided the explosion was a foreseeable result of the defendant's actions.
Yes, a rescuer can bring an action should she/he be injured while attempting to rescue others, but "forseeability", along with "assumption of risk" could come into play.
Texas' "rescue doctrine" only applies to situations where the
defendant created the danger.
Should the intrepid rescuer sustain an injury while saving (attempting to save) the defendant from a house fire, the defendant only owes a duty under the rescue doctrine
if the defendant started the fire.
(Note: Different rules apply IF the rescuer is a trained firefighter.)