Two months old is just about when they get hit with coccidiosis. It's very hard to run a proper fecal on very runny matter. Given his age and if he is not on cocci prevention, I would assume and treat for that. I would use Albon because it is readily available to me. Others use Sulmet or di-methox. Dosage is 1cc per 5 lbs the first day and then 1cc per 10 lbs for 4 more days. I would also give him Safeguard at 3 times the lable dose for 3 days at the same time. This will mildly worm him and will cover Giardia and help expell cocci. Giving him some pepto bismol may be of use to help his stomach feel better and keep him eating well while firming him up. The most important thing is to make sure he keeps enough liquids inside to prevent dehydration.
In the forest dark and deep Do not wander do not sleep...
I always see if a little Cinnamon and water drench can clear it up first. Then if nothing gets better I determine the course of treatment depending on what I think is going on. I never give Pepto Bismal to any of my animals. I can deal with scouring by replacing the electrolytes. I also offer Berry Gatoraid in a gallon of water. What I want is the toxins OUT, not inside in the gut. Which is a whole nother problem. That is why I let it take the course. One thing that really helps is too scrub all buckets and pans out. Keep the bedding as clean as you can. Wear dish gloves and keep the kid clean. That all gets frustrating I know while whatever bug runs the course. It could be a moldy piece of hay, coccia, salmonella, ecoli, worms, virus, allot of things but first I try the simple treatment and time. Here are some barn note charts from when my triplets had runs. Cinnamon 1 teaspoon per 6cc water drenched over an hour or so slowly with a needleless syringe. Given Pro bios Paste. Next day, .05 Power Punch with a Tums crushed between spoons and dissolved for 10 minutes, Scrubbed all buckets and tubs. Removed all bedding and hay from stall. Took away all first cut hay. Changed hay to the sweet pickle smelling hay 2nd or 3rd cut. It is a bit brighter green and finer in texture than the stuff I removed that was also sun bleached. I also NEVER feed outside of the roll to kids. My rolls are cored and they only get center hay. Cuz the outside usually needs to be looked at for any moisture that got on it, especially if it is bottom stack. I do round rolls 750lbs+. I also gave my kids Pedialyte from the baby isle at the store, They love the strawberry. Hope that your kid gets better. Maybe the grain was too rich. Is it a concentrate?
I don't know how much grain he got but maybe too much so for your case I would consider some CD AntiToxin subQ. Adults get double dose for therapudic but for kids I usually follow the bottle instructions. If he starts foaming and grinding his teeth, has seizures, cries out in pain and bloats with a rocking horse stance then you know his kidney could be getting pulpy and to treat for enterotoxemia. Hopefully his mother had her CD/T shot up to date prior to kidding.