So the RSU of €10K and the shares of €150K are off the table, any redundancy to add to the pot? You will know for definitive this year sometime.
Currently your Mum
€220 equity in home
€35K debt
No pension lump sum if she has a debt?
€? Clawback to council if moving
You
€200K equity in home
€35K savings
€250K mortgage
€? Stock in previous employers company
AIB do
top up mortgage one of their options being “support for family buying a home of their own” but
Avant don’t offer this option. So the only way you could release €100K from your house would be to switch lenders and apply for a top-up but I don’t know how feasible that all is. Each step may prove to be impossible due to individual circumstances.
At the moment I think the only thing you can do for you Mam is to give her an interest free loan to pay off the debt of €35K, then you give it 12 months to see if you get anything on the old share option, build up your savings and wait to hear what the council says.