Old dog with sudden syncope events. End of life care advice

We have an 11yo diabetic, lumpy lab mix who had 5 syncope events between 11pm and 8pm Wed-Th (yesterday). Two happened at home before going to our regular vet, who thought they might be seizures but wasn't certain, then another one happened wheb we got home. We took him to an emergency vet where they saw another event and determined syncope. After an initial cardiology consult, there doesn't seem to be any issues with his heart structure or arrhythmia that they could see in that brief time. Our next options are to consider more tests, but we've already spent at least $1200 and are looking at another $2k-$5k. Other likely causes could be a tumor somewhere, cancer, or something unknown. The emergency vet mentioned a recent patient who had a similar situation and they never found the root cause.

So we pretty much know we're done with testing, but my husband and I are in different places regarding end of life care. He feels strongly about not wanting him to suffer or put him through unnecessary pain and wants to consider euthanasia potentially today or tomorrow.

I on the other hand want to see how the next few days go. I think yesterday ended up being a stressful day which may have caused more events. I want to see what a few regular days look like for him. He doesn't appear to be in additional pain due to the syncope, except during the events. He is old and is on pain meds for arthritis.

My husband is highly concerned about the 5 times yesterday that he wasn't getting oxygen to his brain, which I absolutely think is fair. If it was clear it will happen to him at least once daily, I would feel better about a decision to euthanize soon.

I guess I'm wanting additional opinions on whether keeping him alive knowing what we know today is hurting him. Or what the potential effects of, say 2 syncope events per week (not enough blood to the brain), are in the short term. Or just what others would do in our position, knowing we probably won't do anymore testing. He still enjoys going for walks, seeing people he knows, etc. But he is old and in general just lays around most of the day. It seems like the steps to our back door could be a trigger because the first one is a little high and he has to jump a bit to get up.