assalamu haleikumwe live in a western country where there's a lot of riba and nowadays my parents dont even care about it,my dad just bought somethi with riba,and i told my mom and she said we don't have money,there's no way i can stop them from committing riba,

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

First of all, may Allah reward you for your concern about this matter and for being keen on advising your parents to avoid dealing with Riba (interest and/or usury). Indeed, you have done well.

There are many means of lawful earning for whoever seeks them, and does not take the issue of dealing with Riba and consuming what is forbidden lightly. Allah Says (what means): {And whoever fears Allah - He will make for him a way out. And will provide for him from where he does not expect.} [Quran 65:2-3]

With regard to the statement of your mother that they do not have money, then there are some details about this. The need may reach the level of dire necessity that makes what is forbidden lawful. This is when the person reaches a condition that if he does not consume Riba he will die or nearly dies. However, the need may not reach this level, so it does not render what is forbidden lawful.

In any case, you should endeavor to advise your father in the best manner that you predominantly think would be beneficial for him, while being kind and dutiful to him, and being gentle with him so that he would fear Allah, and seek to gain lawful earnings. Allah will make things easy for him after hardship if he fears Him, because He promised so.

Allah knows best.