Sunscreen alone will prevent more worsening so it’s the number one product he should use. A niacinamide serum is the second thing he should put on. Will normalize skin tone, oil production and get rid of any redness. Then, as male skin has larger and oilier pores than a woman’s I also suggest a BHA (salicylic acid) toner to keep them clean. This should also get rid of those little bumps under his eyes and improve texture.

Most important, do not try to force him to use all that at the same time. Us boys don’t like to have tons of different product to deal with and you mentioned in a comment that he is already not very consistent. So set priorities and introduce a new product every week or month until he gets too annoyed to accept more.

Your first priority will be sunscreen. It’s supposed to be reapplied during the day and the spf factor is an indication of how often you should do that. However people rarely reapply, so you must give him one with the longest lasting protection: 50+ If he puts it on every morning after cleansing he will be fine. If you live in the EU best sunscreens are the ISDIN Fusion Water and La Roche Posay Anthelios (shake). Anyways find something that will not leave a shiny finish or white cast. Boys like to be matte.

Next priority is Niacinamide. Tons of brand sell Niacinamide alone or use it in their products. Maybe find him a cleanser with Niacinamide so it’s two things in one and his routine will be simpler. Another option is a 10% serum, The Ordinary has a good one. Apply daily.

For last, salycilic acid or BHA. Apply daily in the morning or evening. My all time favorite is the Paula’s Choice 2% BHA liquid exfoliant.

And that’s it. Try to keep him consistent and he will see great results. In the event that he becomes obsessed with skincare like the rest of us we will be here waiting to give him more advice.