Yes, Eren did eat his dad.
It’s a really emotional part of the Attack on Titan story. Grisha hands over his abilities (those of the Attack Titan and Founding Titan he just acquired) to his son, Eren. Eren becomes a Pure Titan when he consumes his father’s powers, taking them for himself.
Did Eren’s dad want to be eaten?
Probably so. It appear’s that it was Grisha’s desire to have Eren inherit both the Attack Titan and Founding Titan powers.
Grisha gave his son the key to the basement, indicating he did want Eren to inherit the powers by eating him.
