I have an 1 year licence since being diagnosed with Epilepsy at 48 (I am now 63). I have re-apply every year & most years I have to have an Independent Medical in addition to a report from my GP. DVLA pay for this but not my travel expenses, this year I had to travel up to Taunton from Devon (50 miles each way).
I agree that there should be stricter controls on over 70s, eye test mandatory, I would like to have a Medical Professional input rather than the driver completing the form, how may think they are fit to drive but a Medical Professional may think differently.
My DM was still driving at 87 until the Hospital told her her eye-sight wasn't up to standard. She still feels she is ok to drive but had to listen to advice, she is resentful as she has to rely on other people, no buses, no shop etc in her village.
Not sure I'd be brave enough to tell DoE that he couldn't drive but I suspect Police will have advised him & DVLA could revoke his licence immediately if there doubts about his fitness.
As for sun , I drove back from Somerset to Devon on A303 a couple of weeks ago, there were times when I almost lost sight of the road altogether & I wasn't crossing/pulling out into traffic, driving when the sun is low is a nightmare.