My brother recently died and left his home to a friend , is his estate liable for any damaged to his house ?

The estate, will likely be entitled to receive either aid from FEMA or repairs based upon homeowners insurance.
The estate is not responsible/liable for the damages but may have an obligation to apply for insurance repairs and FEMA aid ect if available.
Talk with your probate attorney about these issues.

The estate, and you as executor, do have an obligation to reasonably protect the property. This would include doing what is necessary to restore the property without coming out of pocket yourself. As executor, you will need to hire a probate attorney to ensure your duties are performed properly.

The estate has the obligation to protect the property to the extent possible prior to its distribution to the friend. If damages have been incurred then the you as personal representative should contact the insurance company and or FEMA seeking recompense for the damages. You need to contact the estate's attorney as to the best way to proceed.

The estate does have an obligation to protect the property. If there are damages, then the personal representative (you) needs to contact the insurance company and FEMA in order to seek compensation for the damages. Make sure to speak with your Probate Attorney.