A/C systems have a refrigerant pressure sensor that will disable the system if the pressure drops below a certain level. Refrigerant can leak slowly over a period of years past rubber seals etc. With a car this age a recharge might be all it needs to continue working for a few more years. It may not need a leak 'fixing' as such , although air conditioning specialists do have a legal obligation to refuse any request to simply top up the system 'to last the summer' etc when its evident there is a significant leak.
Some air con places will do 'free' pressure check, although of course they are looking for chargeable work so may be biased.
No offence intended about your car but older cars can reach an age where its no longer economically viable to carry out expensive aircon repairs. For those willing for a bit of a challenge you can buy DIY aircon recharge kits, which include a pressure gauge and cylinder of refrigerant. You need to buy the correct type for the age of car. Most 'older' cars use R134A, newer one use the more eco friendly R1234yf (which is usually more expensive as the makers still hold a patent) . I think you can also buy versions containing a sealant that might fix some minor leaks. The whole kit can cost less than a recharge by a specialist and could possibly do more than one top up. But its a bit of a gamble. If the refrigerant quickly leaks away again you have wasted your money (and polluted the environment) and using one with leak sealant might permanently gum up the whole system. Aircon specialists dont normally use sealant as they cannot guarantee it will work or wont cause more problems, and they lose expensive repair work.
Its also possible to buy just the gauge without sealant (from about £9 ) to do your own unbiased pressure checks (and maybe also for family and friends)
https://www.ebay.co.uk/itm/365219808977?
