If he died before Jesus that is likely true but still would have been that day. However if you recall Jesus was already dead when they broke the legs of the other two crucified with Him. Jesus was waiting for the thief and what a joyous meeting that must have been
Therefore Jesus had died first.
So Jesus was waiting for the "Good Thief" with open arms, and, yes, with all of the myriads of the saved, streaming into Heaven from the Abode of the Dead --- Adam and Eve too ---he rejoiced!
The only part that I have a hard time with - Jesus didn’t go to Heaven (paradise?) the day that he died. He went to Hell. I’ve heard some say that it would seem like “today” when the thief got to heaven - no notice of the missing time.
I wonder if it is just like anybody that accepts Christ. That day is when you have eternal life, and begin to live in the Kingdom.
Romans 8:10-11
If Christ is in you, though the body is dead because of sin, yet the spirit is alive because of righteousness. But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ Jesus from the dead will also give life to your mortal bodies through His Spirit who dwells in you.