even if the solicitor does not have knowledge to deal with this he would have to pass it on to another colleague or firm (he is bound by the law society to give all services and advice to his clients)
If her signature has been forged, then she does need to take action, worrying about the relationship with the child is just an excuse to not do anything.
I know this seems harsh, but i deal with lots of bailiff/insolvency work on a daily basis and see some terrible things and one of the main reasons people get away with leaving a partner in debt, crying in their sitting room as we empty their house is as the partner didn't want to upset the children.
by the time they realise that the children have now lost everything in their home, they then decide maybe they should have gone after the partner, but unfortunately it is too late.
my advice, push the solicitor to get this looked at and if he/she won't then find another solicitor.