If your tenant is not paying, you should issue a signed notice that this tenant should pay the rent or quit (move). If the tenant fail to pay the rent current or move you would be required to file for a legal eviction through the court system
Not having a new roof is no reason for your tenant not to pay rent. You are being played and being played big time.
You should have long ago issued this tenant a written notice to pay rent or quit.
A judge would sign a legal eviction notice for your tenant to leave the rental unit based on the eviction laws of your state.
It might be to your advantage to give your tenant a written notice to move immediately. If a legal eviction is required you would be ahead of the game. The house would be vacant prior to the close of the sale transaction
Once the tenant is no longer residing in the rental unit you are able to take this tenant to small claims court to sue for any back rent and late penalties for not paying the rent on time to include any damage to the rental not covered by the deposit.
You are able to place the house up for sale. In using a real estate agent, you would want to make sure the tenant is introduced to your real estate agent so they would be able to make arrangements for potential buyers to be able to see the property.
Having tenants in the house might be a problem with showing the house, the condition of the house, and the negative comments made by your tenant toward any potential buyer, however your tenant is not able to prevent you from offering your house for sale.
Getting rid of your non rent paying tenant is paramount. Take the necessary action to get rid of this tenant. You would be in a better position to show the house for sale. This tenant would impede any potential buyer with negative comments.
I hope this has been of some benefit to you, good luck.