I feel obligated to point out that that WHM/AST log is a straight up WHM pad run. The WHM is given a single target balance on pull and everyone else lays off the adds so the WHM can Holy pad as much as possible. It's still a solid effort and an even healing split, but the end result damage is intentionally slanted.
Does it mean if I only heal 3k-4 hps in a fight like O5S-O6S it's bad? My whm doesn't seem to dps much and that's apparently cause I gimp him according to my friend. I don't really see how my logs would be boosted at all and it's probably him trolling at this point but technically the best way to play a healer in this game is by dpsing and understanding where the heal checks come in. What's the average HPS that people should pull in these fights? Like, I know Kefka and God of Magic are pretty big heal checks but the other fights honestly are not much of one. So if I go in with the mindset that I can heal miniscully, how does that mean a log is boosted?
So I keep waffling on wading in on this but I really, really, really like to get longwinded about how the game works and the various mindsets players bring into it, and the way healers balance healing and damage between one another and how groups view it is one of the more interesting aspects to me lately.
Last tier, FFLogs added Healer Combined Damage as a metric. This is literally the first thing I check on any healer's fflogs page--how much each individual in a healing pair puts into damage is less relevant than how much damage the healers as a unit manage to push while healing enough to clear. This also has some bleedover into tank damage--healers rocking DPS is less impressive if their tanks it in tank stance full time and the Paladin is clemencying as much as possible. If you notice your personal logs are good but your healer combined isn't great, it's a sign something somewhere is off in the balance between healers. HPS as a metric is sort of a trap--HPS
does not include overheal, and so if you're rolling a regen and somebody tops everyone off with an instant, your HPS is going to not include any of the regen ticks after that are 100% overkill. Additionally, HPS within the same fight is wildly variable based on how the group as a whole handles things. Solid use of mitigation skills by tanks and DPS will ultimately decrease damage taken and, in turn, decrease the amount of healing that is needed before it goes full overheal. Additionally, how long a fight goes on and the strategies used in a fight will make a huge difference in HPS and DPS. The overall group performance has massive impact on how much the healers can get away with DPSing. There's no one answer.
To sort of swing around to the situation at hand, though, in a hypothetical raid fight the AST should almost always be the one doing the bulk of the needed GCD healing. Malefic is the weakest healer nuke, so an AST trading a Malefic for a Helios is a lower raid DPS loss than a WHM trading a Stone IV for a medica. Where things change up a little is that if a WHM can do with a Cure III what an AST would need two Helios casts to do, the WHM should step up because losing one Stone IV is less bad than losing two Malefics. Similar concepts apply if you pair an AST and a SCH--Broil is more damage, etc. The ultimate end goal is always both healers figuring out how to get most healing done using GCDs that don't interrupt their DPS, but when somebody has to drop a GCD it's usually the AST that should.
So it sounds like your particular situation may be flipped--the expectation is that you should be healing while the WHM throws rocks, because the overall raid damage would increase in that situation. If the WHM is having to GCD heal because you're not making the most of your oGCD healing abilities--Earthly Star underuse or misuse is one of the more common ways ASTs miss out on a lot of free healing--then the WHM is helping artificially boost your results by covering healing spots you should be handling. The way your pairing works in practice may not line up with what's optimal.
That said the only people who can tell you if this is a real problem or not is the White Mage and the rest of your group. It's not entirely uncommon to find healers that absolutely do not want to DPS and are uncomfortable doing it; this is 'wrong' in the sense that it's going to lead to overall lower group damage than you could have, and may make passing DPS checks harder for the group, but provided the cohealer and the rest of the static do not mind, it's not the end of the world. If, however, your cohealer would like to DPS more but feels they can't because they're trying to cover healing you're not doing but could, it's worth talking it out with them and seeing if you can come to a better arrangement. If there's a spot they feel like they have to medica, maybe an adjustment in Earthly Star timing helps without costing anything.
Taking 5 as an example, you can get through the fight with very few GCDs spent on healing by either healer if you plan oGCD usage properly and mitigate things. Looking at one of the trying to speed clears we did, I have 3 GCDs spent on healing (one Aspected Benefic on a tank, two Aspected Helios during adds when there's nothing to target) and some Collective Unconscious uses and the SCH has three GCDs spent on healing (two deploy adlo and a succor) and three Aetherflow stack uses to heal (two Indoms and an Excog). This is a pull with 100% Selene uptime, so no Whispering Dawn, and the greedy standing super close for Head On strategy so people are taking a lot more damage there than usual. But because oGCD healing is so strong, and we planned out exactly which skills we can use for free healing, we can get away with very few GCDs used--I actually have 60% overheal still, because Stellar Explosion and Indom and such are so strong.
So if your minimal healing mindset is creating a situation where the WHM is spending a bunch of GCDs on healing stuff that doesn't meet your criteria for a healing check, your friend has a point. That'd lead to your DPS being at the expense of the WHM's DPS, which isn't ideal and you guys should talk things out and plan oGCDs so you can both do better. That said, if your WHM just flat out does not want to DPS and your group is fine with it, there's not much productive you can do.