The general rule with regard to whether litigation costs are recoverable or not is that you would not recover them unless court proceedings have been issued and then, even if they settled, without actually going to court, you would recover your “wasted costs” although to be frank, that could often be part of the negotiation that there is “no order as to costs”.
Therefore if your father was being difficult and it actually settled in your favour, it is very often the case that the cost of the argument is going to be more than the amount recovered and that’s the situation that your father is in, it settled for GBP25,000 but you have spent GBP25,000 on the argument and you are entitled to recover that loss of course he would have to pay his own costs so the net result is that this would cost him a shed load of money for nothing.
If the estate doesn’t have enough money to pay him, and it comes out of his own pocket, remortgaged his house raise a loan, whatever. His fault for entering into the litigation in the first place.
My personal opinion is that the estate doesn’t cover these costs in these circumstances, he would cover them.