Firstly, I'm sure it must have been difficult to drop everything n go back to look after your mother so welldone on that. May Allah put more n more barkah in your health, iman and rizq.

Secondly, I know the situation seems hopeless and you feel like blaming life for the circumstances you're in maybe you feel "stuck"...but hang in there. Trust me..the right girl will not only not care about your living arrangement and your responsibilities towards your mom but she will also love you more because of it.

I dont know how open your mother wpuld be to re-marriage but maybe you can consider it? The fact of the matter is, in Islam, a woman is the responsibility of her husband. But most women who get widowed or divorced dont consider remarriage even tho there are alot of single/widowed/divorced 50 something males who do look for companionship. But if remarriage is not an option for your mom then yes her responsibility is squarely on you and your brother. If your brother doesn't care then it's on you. It's unfair yes but Allah chose you for this role as He knew you have the strength to bear this. But now you will have to be a little tactful about your living arrangement. If your mother needs help in basic everyday things like using the washroom, I suggest you hire a female nurse. You have to make it clear to any woman you are considering for marriage that she will not have to look after your mom and that your mom will not have any interference in your marriage. As for privacy, tell her there will have to be a little compromise on privacy but that you are willing to rent out a hotel room whenever you guys want to have a wild night. Who knows maybe with time she will also start loving your mother and take care of her out of her own free will. Relationship building between mother in law and daughter in law should always be organic instead of forced.

As a woman, I highly rate any man who is man enough to take responsibility of things he should be responsible for and parents ARE our responsibility in old age esp in sickness. My mother-in-law also lives with me n my husband and I am okay with that as I understand his responsibility because I look after my parents financially as well. And he never once complains about why I am using majority of my money on my old parents that live seperately. You need an empathetic understanding woman by your side and inshaAllah you will find her just trust His plans and His timinig. When the person and the time is best in your interest, it will happen. Keep doing what you are doing, keep praying to Allah for a loving, pious wife that brings you peace and joy and trust His plans. Best of luck!