Unfortunately she cannot get along well with my wife. My wife will always want to pick on her bad habits and scold her and cause difficulties to her. Of course my mum has some ignorances and bad habits.
You committed two major mistakes:
1. Imposing your beliefs on your loved ones. Doing so against their will only result in discord.
2. Trying to change others. We can’t change others unless they are willing to change. Furthermore, it takes a skilled teacher to try help someone change. You are still at the student level, please concentrate on changing yourself first.
There is something called Buddhist humility. We work hard at changing ourselves first instead of trying to convert or save others.
You should consider other options such as separating them: placing your mother in another home. This is more agreeable: you can frequently visit her there. I would prefer this alternative first before bringing her home especially since you have not gained your wife’s consent.
To try to resolve their mutual enmity is quite difficult. I am afraid I cannot give you a good answer through this medium.
In brief, I applaud your good intentions. At this stage of your cultivation, you cannot meddle in others’ affairs yet. You may seek personal counsel from a wise teacher who can provide more clarifications on Master Hua’s teachings.
In my humble opinion, the best way for you to practice filial piety is to help your mother obtain rebirth to the Pure Land.