No shampoo not for everyone?

My husband and I have been trying several "green" and "natural" home solutions for cleaning (and not just ourselves). For many years he has used white vinegar to wash our clothes. This has been great for us. They are fluffy and smell clean. Not fake fabric softener fresh, but really fresh. He also used straight vinegar in a spray bottle as a household cleaner before we even met. We have gray water runoff and we actually noticed grass dying where it came out of our house. He thought it could be from our dish liquid and shampoos. We quit using detergents and this problem quit. We have been trying several homemade shampoo mixes lately (3 months). It has been fine for my hair but terrible for his hair. His scalp is clean feeling (and looking) and his hair looks great but he is getting very bad acne (in the way of infected hairs) all over his scalp. They get really bad and very painful. We have tried different solutions at different ratios and the problem persists. I've even been washing his hair for him to make sure he isn't doing something wrong. He isn't. Three days ago he bought a bar of Burt's Bees peppermint and rosemary. He washed his hair once and the problem was better overnight. He doesn't like this because he is skeptical of anything commercial. The ingredients seem fine to me and I've been trying to tell him to keep using it about once a week to prevent his problem. The ingredients read like a homemade bar soap. Veggie soap base, peppermint oil, almond and rosemary leaf powder. He knows the company is owned by Clorox (I believe) so he doesn't trust it so much. We live in a very rural area so natural stuff is either made at home or bought in the form of Burt's Bees (which seems pretty bad for liquid shampoo but pretty good for salves and bar soaps), Tom's of Maine (he won't use at all) Nature's Gate and one or two others. I've been trying to tell him I've read rosemary and peppermint are supposed to be quite good for your hair and it seems to be helping him quite a lot. It also has a very straight forward and limited ingredient list. We don't really have time to make actual soap at home so I'm wondering if this is a good/safe substitute for homemade? As long as it doesn't seem to be stripping his hair of oils (his is very oily naturally) and prevents acne should he keep using it from time to time? I don't know about these things. Baking soda and vinegar seem to work great for me but nothing seems to work for him.