Even if a young therapist were capable of understanding where an older patient is coming from, if the patient doesn't get the feel that this is the case then it is useless.
A younger therapist can work with an older client perfectly well, indeed if the client is old enough then it is probable that the therapist will be younger, given retirement ages and so forth. Many therapists do some private practice beyond retirement but usually just a few hours here and there.
People often put it down to 'life experience' - an unsatisfyingly vague term but an intuitive one. If you've been around the block and seen a bit of life, had your highs and lows, come out of the other side, been knocked down, got back up, once more round the block, etc, etc, etc. It all congeals into some nebulous resource you can draw from. It can't be taught and can only be accrued one day at a time. Worth remembering though that some people do more living in a year than others do in a decade in some respects. The big questions around mortality, ageing and vulnerability seem very age dependant.
I'm interested in how client's are allocated to counsellors, following assessment by a senior person. Sometimes it makes sense to place like with like (age,gender, outlook) with a view to fostering identification. Other times it makes sense to place people with the sort of person they would wish to avoid - to provide scope for appropriate challenges. For example men who are afraid of women might get more out of working with a female, women living in the long shadow of an overbearing father might work with a male as this promotes transference of old issues into the current moment facilitiating their exploration.
Many people are very uncomfortable with the idea of male counsellor's working with females who have been abused - especially when sexual abuse has been involved. Any benefits in exploring their attitudes to males are overrideen by the risk of retraumatising the client and leaving the client feeling unsupported - the popular idea is that only another woman can really empathise to the requisite degree.
I've discussed this with female friends who agree they would want to only work with a female but can't be clear as to why. One likened it to the idea of male primary school teachers, observing that secretly most women don't want men teaching their little ones but they'll never admit this freely, although all women know where they're coming from.
I thought this was unfair to all of the men who care about children and education but my friend's reaction was, "Maybe it is...but why take the risk?"
Going back to my earlier point - are there degrees of vulnerability when working with people when a cut-off point is reached, beyond which only women are to be trusted to proceed safely? Where does this notion come from? How universal is it?