This sounds remarkably similar to my past, except my Dad had probs with gambling.

My Dad died when I was in my teens and I spent the best part of my younger years caring for my mum and missing out on having fun with friends, settling down and having my own family.  My brothers shirked any duty of care for my mum and happily carried on enjoying life, eventually getting married and having children.  They had parties and meals with each other, but failed to invite my mother or myself.  If I made any gripe about it - it turned into an argument.

In my late thirties, after years of depression, I eventually stood my ground and refused to go on holiday with her, so she went on her own.  She subsequently met a man on the holiday and started a relationship - my help was therefore no longer required and I was 'dumped,' only to watch her going out and enjoying herself.

Anger is an understatement.

Although I have now bought my own house, found myself a nice guy and now comfortably settled, my 'family' years are more or less over and there is little chance I will have children of my own.  In some ways, I resent my mother for taking this away from me, and I resent myself for letting her.

The only advice I can give to you is that it's your life, you only get one chance - live it.  Don't be dictated to on what you should do.  Be there for your mother when she needs you, but don't put your life on hold for her.  If you do, you will only end up like me - bitter and resentful.  As for any siblings, let them complain, let them say what they want - ignore it and walk away.  They'll soon understand that they can't dictate your life for you.  If their only attack is to disown you - let them.  You will often find that friends are worth their weight in gold compared to some family members - and there are plenty of people out there to be friends with.

Hope this helps.