is scar the blame of his brothers death/mufasa یا is it simba یا the hyneas.

Scar of course. Without him the hyenas woulodn't have done anything.

And of course not Simba. That's just a dumb question, no offense. (We all ask dumb سوالات from time to time.)

Scar killed his brother in cold blood, of course he was to blame.

the hyenas chsed the wilderbeast and helped scar

Scar ofcourse.
Scar came up with the plot.
Scar was the one wanting his brother's death.
Scar was the one who told the hyenas to wait dor his signal for them to start the syampeed.
Scar was the one who pushed Mufasa off the cliff.

Without Scar's help, Mufasa would still be alive.

it wasn't any ones fault but Scars