hey,

im not a fig expert, just a new hobbyist, but with these issues it sounds like it needs to be re-potted. watering depends on many things- mine are outside trees in pots, and i will water them once a day only if its HOT out. it depends on pot type, where they are etc, but if theyre in pots i generally water when the soil is dry an inch or so below the soil.

hope this helps, good luck!

Over watering is more dangerous than under watering. Don't water the plant until the soil starts getting dry. Let the soil tell you when to water. A large tree will drink more water, than a small tree, so the time schedule will be different, depending on conditions.

I water my trees every two or three days, if it doesn't rain. But I water every day if the weather is hot, and the soil in the pot drys out quickly.

It sounds like your tree is in very bad shape. I don't know if it will survive. Take some cuttings of the tips and try rooting them in damp potting soil, or sphagnum moss.

Try to save the tree, by letting the soil dry out some, and see if that helps.