Itachi solo'd the whole family .. Imagine what Madara would do.
No Itachi didn't solo the whole family, he had Obito's help who was on Minato's level. Also Itachi's parents let themselves be killed and it was a surprise attack during the night so it wasn't a fair fight at all.
For all we know he let Itachi kill him because he wouldn't want to raise his hand against his own son, maybe he saw it was all over and decided fate to take its course. For all we know he has a MS and it will be revealed to us lol.
Your post just sparked an interesting theory in my head. What if Sasuke's parents immediately awoke the MS right before their deaths at the hands of Itachi? So he revives them and all three of them team up to fight Madara lol.xd
OT: Fugaku was probably a high jounin level ninja or low kage at best. Probably slightly weaker than current Kakashi or slightly stronger than part 1 Kakashi. In other words, unless he has a MS, he'd get owned pretty easily and even if he had one, I doubt even with Sasuke's help, they would be much of a threat against Madara unless Sasuke unlocks another power up or shows us some more EMS abilities.