Need advice on possible benefits ...

A friend of mine has recently handed his notice in at his workplace as he could no longer cope with his job (he suffers from clinical depression).

He rang in sick the same day he resigned, but his doctor says he cannot help him as regards incapacity benefit, even though he's in no fit state to work.

Can anyone please help here?  Does this mean he's entitled to no benefit (he has got savings over £8k)?  Is it perhaps a case for the CAB?

The savings of over £8000 will prevent a claim for Income based JSA, His six months contribution based JSA will probably be sanctioned by his giving in his notice rather than waiting to be sacked.

I feel he should claim Incapacity Benefit. The criteria for which are set out here
PCA Calculator
Further guidance on claiming IB on mental health grounds can be found here
BenefitsandworkIBguide
The fact that his GP doesn't support his claim will make life very difficult. He could consider changing doctors? He could ask his GP for specialist support for his Depression. There should be a Mental Health Support service which should be able to offer Cognitive Behaviour Therapy or counselling or other support via a CPN and this person will be better able to provide the necessary support for his IB claim. The DWP will be obliged to conduct a PCA and your friend should if he keeps a diary or log of current behaviours consistent with the descriptor statements set out in the calculator above and detailed in A guide to the personal capability assessment
be able to suceed with this.

If his doctor isn't prepared to support his IB claim there is very little point in considering a claim for DLA on Mental Health Grounds. He would need to be a danger to himself or others for this to be viable. While you may be justified in feeling somewhat antagonistic to his current GP you should take account of the fact that for most depressed people being in work is better for them than the alternative of being out of work. While he may be able to survive on his capital resources for a while it is difficult to see how this can be a viable long term solution and so it would be best if support for his mental health problems is pursued as a matter of urgency.

I generally find from now until January is progressively harder and things only start getting better around May. January is the peak season for suicide, so do take this situation seriously. Each of the following may be able to provide local support not only for his benefit claim but also with the self-management of his condition.
Netdoctor Depression Test
Sane
Mind Uk
Manic Depression Fellowship