To be honest, not totally sure about Donnie and Johnny. I CAN say...

Donnie's EX bought my Dad's house about 29 years ago. While she was in the process, the Van Zant's Dad...Lacy, helped her out. It was an amicable split and Lacy was helping her through the process. One day, while at my Dad's, Lacy Van Zant and I chatted for about 45 minutes. He was like Uncle Jessie from The Dukes Of Hazzard. VERY cool old fella! We talked about EVERYTHING!