Am I still liable for alleged dead tree after selling the house?

[Jack B.]

Days after I had called the cops on my neighbor for yet again parking in my driveway, he texted me claiming my tree was leaning toward his property, asking me to take it down. I asked him why he thought that as it looked the same to me. A few weeks later he sent me a certified letter with some brand new arbhorist from 120 miles away (we live in a big city, he was shopping for someone who would agree with him IMO) to say the tree was dead. Of course he trespassed on my property to assess the tree, and the assessment is questionable IMO.

I've since sold the property. I did not disclose the tree issue to the buyer since it wasn't specifically called out on Form 17 (WA) and the assessment was questionable. I tried to get it assessed before I sold but couldn't get an appointment in time.

How do I transfer liability back to the neighbor for letting the new owner know? Or basically how do I absolve myself from liability here? Send a certified letter to the neighbor telling him to take the issue up with the buyer? Send a letter to the buyer? Or both? Or perhaps the new owner is liable regardless? What do I do in this situation? The attorney offered to send a letter to one or both parties for $500. Something I could do myself. But I just want to be certain I won't be held liable at this point, so maybe it's worth it to pay the attorney for this?