It isn't a case of argumentum ad hominem as this is usually understood. Such a fallacy would would occur in a case like this : I argue for policy X and it is then objected that I previously held a policy incompatible with X. That objection is irrelevant to my present argument for policy X. It attacks a fact about me rather than my argument.
It's rather a case of an appeal not to authority (argumentum ad verecundiam) but to lack of authority. Andrew is not an expert, therefore his views are not worth considering or taking seriously.
In certain areas, this would be a good reason for rejecting Andrew's views. If Andrew is not a physicist, his views on quantum mechanics are not those of an expert where only an expert's views count.
The same argument applies, though not so strongly, to global warming and climate change. The experts don't have so strong a claim to be exclusively heard since the science here is, while pretty compelling, contestable. There's a small margin for non-expert opinions to have a right to be heard. (In case anyone thinks otherwise I am not a global warming, climate change sceptic.)
When it comes to psychology, the experts have much less claim to exclude the views of non-experts. The scientific status of psychology and psychiatry (much as I respect these disciplines) is hardly equal to that of quantum physics. That aside, we are all psychologists more or less. Novelists, journalists, political commentators, business people who strike deals, close friends, marriage partners, acquire a huge amount of practical psychology. Indeed, without such psychology it is hard to see how ordinary life could be carried on.
To amend a remark of the philosopher, John Locke in a different context : nature has not been so sparing [mean, stingy] to men to make them barely two-legged creatures, and left it to psychologists and psychiatrists to make them understand one another. (Apologies to Locke for the alterations.)
No grounds here, then, for dismissing, let alone ridiculing, Andrew's tips.
