Yes! they meet again when they are 20 + grand duke kaffman comes to visit the marquis, viche didnt know who the duke was at the time and thought that jade at 20 yrs old would probably look like the duke. later jade comes behind viche and surprises her and hugs her and says he missed her a lot. he leaves again for the dukes house after that but by that point he knows how to manage his powers (magic) with the dukes help and doesn't get as hurt when he uses it. viche and jade meet more often after that
I didn't read through the novel, I read through detailed spoilers from novel updates:
https://forum.novelupdates.com/threads/소꿉친구를-폭군으로-키웠습니다-i-raised-a-childhood-friend-as-a-tyrant.108366/
viche falls sick and then awakes a few days later and realizes its the day her dad was supposed to die so she runs out of the house and gets a carriage with duffry trying to save her dad, she sees assassins and then eventually jade saves them and they both realize they both went back in the past (btw jade went crazy after viche died in the first timeline so he turned back time somehow but the bad part is that he can die anytime due to the curse placed upon him) because of all that once they return to the manor, jade says his final byes to viche (she's crying because she's worried about him) and then he finally leaves with grand duke kaffman and a time skip happens to a few years later ++ tell me if u want any more spoilers