Or is this a worrying amount to drink?

[RainRainGoAway2020]

DH and I went out for dinner last night. Over the course of the evening I estimate he had around 5 or so pints and a large glass of wine. I went to bed when we got home and he stayed up. This morning I find he had sat and drank 3 cans of beer and almost an entire bottle of wine after i went to bed.
AIBU or is that a ridiculous amount to drink after a night out??

This is something of a pattern with him and I think it’s symptomatic of an issue with alcohol - he denies it. The worst of it is that he drove this morning before I realised he had carried on his own party at home. I’d never have got in the car if I’d had any idea just how much he’d sunk.

I think the answer to your main question is yes, this is too much to drink in one session but there are lots of other red flags in what you have said and I don’t think you are being at all unreasonable to be concerned:

Staying up late to drink excessively on his own and you imply this happens regularly.

He doesn’t seem to have a healthy off switch once he’s started drinking.

He is furtively pre-loading drinks before a night out and cramming extra drinks in before taxi arrives.

Driving his family the morning after a bender and thinking nothing of it.

He is being aggressively defensive when you question his actions.

Less hungover than expected could mean tolerance has built up.

Will drink anything and everything.

Frequently smell alcohol on him but he denies.

Alcoholism in his family.

It is clear that his drinking is affecting you.

Although you will get quite a few posters justifying lots of aspects of this type of drinking, taken together, these are signs that point to an alcohol issue and you are totally reasonable to be questioning it. Unfortunately, as lots of us know, it is really, really hard to break through the denial (you might never) and it sounds as though you are having a tough time with his angry responses to you. What do you want to do next?