I think we should also understand that there are different tiers involved here....
I think a strength coach/lifter with a solid grasp of form and programming but not so "uber" lifts could absolutely assist rank beginners to early intermediates either in person or on a forum.
But a strength/powerlifting coach with a 300 squat/350 deadlift...I personally do not have confidence that they fully grasp my unique demands.
Obviously there are some special cases here...but if I am being honest, I think a 300 squat/350 deadlift is no better than early intermediate and it leaves me with questions as to why this coach has never surpassed these marks.
Strength Standards for Men - Muscle and Brawn - Bodybuilding and Powerlifting
These numbers are intermediate level according to the strength standards for men, and surely reveal that the coach has put in some effort. But I think any trainee that has been lifting for longer than 18-24 months should be able to surpass these numbers...IF they have been training for strength...which, we should not forget, is what our coach is coaching.
He is not a bodybuilding coach who may have lower numbers for whatever reasons. And along these lines...the average person NOT interested in powerlifting who is reading this should NOT assume I am attacking their lift totals. I am not. Please stay grounded in the reality that this is a strength/powerlifting coach and we are talking about trainees who are specifically training for strength numbers.