How come Danzo didn't use shisui's eyes to control Tobi and use him to kill Sasuke?

[Grammar Nazi]

judging by your avatar you are another fan of naruto hating others chars as tobi/sasuke .....as he was stated already DANZO USED shishui eye on tifune,the eye WAS ACTIVATED.

I wouldn't judge someone based on their avatar, in case you havent noticed its naruto with the rinnegan.

Now back to the point, what exactly do you mean by "the eye was activated"? I thought Danzo was deciding whether to use Kotoatsukiomi on Tobi or use izanagi to heal himself again to 100%.

 

[The Hidden Shinobi]

he used it on mifun during the kage summit . and as danzo said, he cant use that tech on a daily basis

This, but I think he can use it like maximum twice a day because in the fight with sasuke after he was stabbed by sasuke's sword (before he took karin) he said finally shisui's eye has returned and he wasn't sure if he should use izanagi or KA

 

[Killer Vision]

he might have known that tobi could counter almost any uchiha jutsu.
exp:
1.Kakashi- kamui
2.Itachi-Amaterasu