He may be able to, he may not.

Depends on how growthy he is for his age. Sounds like he's not quite ready to push his weight around as a buck yet.

At 5 mon, he is a bit young and ought to be right around 60lbs. Height wise, if he's willing, you'd be suprised what they can achieve, lol. My current Alpine March buck was right around 100lbs at right around 5 months according to weight tape - he's a big'un. His sister was over 70lbs with bathroom scale and weight tape. I couldn't lift the buckling, though. :P I feed them durned good because I needed to use that buckling this year and I *hate* dry yearlings so his sister is going to get bred.
Even if you know you can't be present to watch kiddings, knowing a duedate is indispensable when you are trying to manage the does well. Knowing when they need an increase of concentrates, when to vaccinate, etc all influences your ability to be successful.

Being due sometime in February at the earliest, I'd suggest penning due does inside as well while you're away and setting up heat lamps (which scare me for barn fires); Kidding in February without attendance may mean lowered chance of kid survival especially with multiples. Usually if someone cannot attend births, I STRONGLY suggest they kid their does out in May instead of Midwinter... Even if things go well, kids are at a high likelihood of chilling in the cold temps we often have - they're born wet and twins only have one mom to dry them. Sometimes it's just not fast enough, even a good mom. I knew with my triplets and quads born in Early march to good, experienced boer does, I was trying to get them dry FAST in March - And the last time I was doing that it was pretty warm; In the cold years It's not fun drying twins fast, lol. I'm out in the barn several times a day checking kids during their first week of life, as that is the high risk period in their lives - I'm out there checking dam raised as often as I'm feeding the bottle kids. I kid out early March though, I'd expect far less management needed for warmer-born kids. Most shepherds that raise pasture-lamb their sheep aim for May lambs, otherwise success is low even for pasture-lamb raising.