Mourinho, who saw his United side beat Fulham 4-1 on Saturday, has struggled this season.
The Portuguese manager has been under immense pressure throughout the season with Manchester United sitting sixth, 16 points off Liverpool in top spot.
Mourinho has reportedly been involved in disagreements with star players Paul Pogba, Alexis Sanchez and Romelu Lukaku.
They have won seven of their 16 Premier League matches so far though have qualified for the knockout stages of the Champions League.
And the poor form has seen him incur the wrath of Blind, who’s son Daley Blind used to play for United under Mourinho.
“Jose can’t even get the right formation any more,” Blind told the Mirror.
“He has not bought the right players and the football is not based on a playing style with clarity for the players.
“For example, he is always changing his line of defenders.
“One match he has five at the back, then four at the back and, when I look at some matches, he is actually playing with six players in a straight line at the back when they have the ball.
“The positioning of United’s players is shocking. Even Southampton had their lines and positions in better shape than United last week.
“There is absolutely nothing to build on for United when they go forward, either.
“Jose should have bought a proper passer for his midfield. A player who will always choose to pass forward and will feed the strikers.
“At FC Porto, he had Beto. At Inter, he had Wesley Sneijder. At Chelsea, he had Frank Lampard. What does he have at United? Pogba. But he is not a passer.
“It is the wrong choice by Jose to play Pogba in that current midfield role.
“When Pogba was at Juventus, he was playing in front of the defence.
“He can do that role or you let him play in a dynamic role behind the front two, where he keeps entering the 18-yard box.”