If you go to www.directgov.co.uk you can look up what benefits are availabel.
1. Working tax credit is claimed for by the person who is the main carer of the child. It tops up the wages of whoever is working: partner or self, but would be payabl to who ever is the main carer of the child, so herself, paid in addition to child tax credit,
2. Regardless of his income if she has worked for the required minimum period of time (direct gove will tell you) and she has paid enough tax she is entitled to jsa for a period of time, unfortunately it is only available for those who previously work and paid tax
3. housing and council tax benefit are payble to help with those to anybody on a low income + those on income support. If she is entitled to working tax credit or child tax credit she will almost definitely get something toward rent/council tax. Ring or vist your local authority office and ask for housing/council tax benefit form, follow the instructions, done. They do require all proof to be origninal, bank statements (proof no savings over fixed amount, but it's quite high), other benefits she receives: child benefit etc. it will tell you what they need.
4. I was previously in her situation with a hubby (yes, stupid enough to marry him) and eventually i got out and am sooo much better off now emotionally and financially! But, she has to come to that decision on her own and it can take time, meanwhile she can contact AL anon for family/relations of those who drink, hopefully they will help her whilst in the situation.
Hope this helps