For:

It is a possibility he was too tired of life he wanted to die.

He started getting very down from this scene:

“Is this it? Is that what it's all about,
Manny? Eating,
Then what?
drinking, snorting, f***ing?”

Plus his wife left him, he killed his best friend, his sister started hating her and he knew sosa was coming to get him but still he does not leave the house or get some security, no he wanted to fight alone, and he probably knew he can’t survive fighting hundred people.

He wanted a dream, when he got that dream; it was nothing for him to do, he wanted to end his life.

Against:

It was Tony Montana, he was too strong to commit suicide

What do you think?