Help and advice

Please can anyone give us some advice?. My uncle died in November 2019 after a very short illness ( pancreatic cancer). He came to Spain in 1988 made it his home worked here paid into the system had become a Spanish pensioner. He made a will and had paid for his appartment. Lived very frugally. So although his death was pretty sudden we thought he had sorted everything even paying an insurance for a funeral so we weren’t left with debt. The appartment was to be left to me and my sister his nieces. He had no children of his own and it was to become a family holiday home. 
while we had started the proces in Spain in Jan everything has been on hold until now. This is where the problems start. Just had an email from the solicitor informing us of the costs. Inheritance tax ,land tax, notetory costs, certificates etc etc!!!. Which amounts to just under €15,000. We cannot inherit until this is paid but to inherit we need to use my uncles estate ( money in acc) sale of the car etc to pay. The insurance still hasn’t settled our claim from the funeral that took place in December after we bought him to the Uk to die. Insisting they cannot pay into the deseased  Acc but also won’t pay into an overseas uk acc. Obviously we can’t open a Spanish bank acc without the Nie which is part of the solicitors costs. Will we be given any time to pay this? What happens if we can’t pay? Neither of us are in any position now to pay this since Covid so we are stuck between a rock and a hard place. 
it’s emotionally difficult as we haven’t even be able to go to the appartment and sort through his personal things. Any advice greatly recieved