The offer Real Madrid received for Vinicius Junior from Saudi Pro League clubs is tempting, and if Real Madrid decides to let Vinicius Junior move to the Saudi Pro League, the money they will realize from the Vinicius deal will help them sign a lot of players from different clubs, but I think Real Madrid isn't yet ready to sell Vinicius Junior, and Vinicius Junior won't want to move to the Saudi Pro League because he still wants to play for Real Madrid and have a chance of winning personal awards like the Ballon d'Or Award, so any possible deal for Vinicius Junior to move to the Saudi Pro League won't happen this season.
Real Madrid is not in a condition of financial difficulties so that selling Vinicius is not a good step because we know that Vinicius is one of the important players at the club. He has an important role in the squad and let himself go, just like looking for problems. Financially Real Madrid is very beneficial with the results of the sale but looking for a player like him is very difficult.
Xabi Alonso still enough to believe in Vinicius's ability and he became an important part in the squad. Besides, Vinicius is still under contract with Real Madrid and I'm sure he will decide to stay in order to pursue more achievements compared to moving to the Saudi Arabian League.