Q.Old Fig tree
A client of ours has an old fig tree with a thick trunk approximately 80 cm high from which the branches are growing. There is not much new growth. We thought it would be nice to keep the fig but feel that it must be pruned to encourage growth and give fruit, but are a bit worried the best way to do it because the last time we pruned a large old fig about the same, it died. We were really surprised because we know how hardy fig trees are. Maybe the heavy pruning was a bad idea? I could send a photo if it would help.
Perhaps, this article will be of some help: https://www.gardeningknowhow.com/edible/fruits/figs/pruning-fig-trees.htm
You can prune it, but you do not want to take off more than 1/3 of the plant at a time. The problem you have here is that tree is very old. Judging from the growth it has, it is near the end of its days. Trees have life spans just like animals. Pruning the older wood likely will not encourage new growth.