I have an uncle exactly like yours. So, my advice is, if you do return his call keep your conversation formal and polite. Don't confide in your uncle, since you know he is the family gossip and likes to spread rumors. Sounds like a stand up guy -- not!!

Set boundaries. Let others know what you will and won't tolerate, esp. with family members who are toxic to your well-being.

If you call your uncle back, be very aloof and formal with him. You don't owe him anything. Period. Be polite but formal. If he tries to bait you into a confrontational, emotional conversation, shut him down with a polite good-bye, thanks-for-calling and hang up.

I deleted my uncle from my Facebook too because he sent me a message shaming me for posting a literary quote that had a curse word in it. I messaged him back and told him that his choice to shame me was petty, and this wasn't the only thing he's done to me over the years; he's always shamed me in person at family gatherings, and his own son (my cousin) molested me when we were teenagers, and his other daughter (my other cousin) was a drug addict and alcoholic for years until she moved out of my uncle's home and got far away from him. Then just recently, my uncle sent me a one-line email, asking me to forgive him. I simply replied, "No. You have never been a source of support or positivity to me and you are not someone whom I need in my life anymore. Please don't contact me again."

Well, this email became broadcast news to all of my extended cousins on my Mom's side of the family, so I deleted all of THEM from my Facebook except for two cousins whom I no longer view as a threat to my well-being, whom I keep very detached connection with on Facebook. And I don't regret estranging myself from that uncle. My sister and brother have visited that uncle and aunt and since I'm the family scapegoat, they are accepted whereas I am not.