Buying my mums council house?

hi my dad died 2008, and what a beautifull man he was, missed greatly, he was very talented, a great artist and great pianis,t overall one of the best very unique , anyway my mum and dad lived in this house for a very long time and dad done so much to the house , when my dad died i moved in with mum to look after her, we thought that i would be able to go on the tenancy with my mum but council wouldnt allow it, so we looked into buying it as all my dads memories are there, as i am self employed and not on big earnings, and im a single parent , and look after my granddaughter whom is 4, for my daughter to work, so no chance of getting another job to make my earnings anymore ,im also a carer for my mum as she is disabled mum does get a dissability benefit , we looked into getting a mortgage between us, but mine and mums earnings are to little. and our ages are against us im 48, and mum is 69, does anyone know of any way round this would really appreciate all of your answers thank you for taking time to read this. also if you would like to see what a wonderfull artist my dad was please take a look at this thank you petertudor.co.uk