I don't know of any specific law(s) govering our profession in general but a condensed version of my past 35 years on the market (north-west EU) looks like this:
Retirement age, when determined by
- law, normally follows the right to receive some kind of state pension,
- [collective-]working agreement, can both be mandatory and voluntary i.e. permit retirement before being terminated and is generally coordinated with the retirement benefit provisions of the contract.
The special problem we have as air crews concerning the health related unfit for flying situation, before retirement age, is normally solved by a collective or private insurance (Loss of License).
In some cases one may be eligible for a public disability allowance but generally it takes less to be grounded than being considered disabled.
Hope it helps!?