Hi
I am very sorry about your loss. Move your remaining boar next to the girls for interaction through the bars but masure that he cannot get at them until 6 weeks post-op. The little baby in my avatar picture on the left is the unplanned legacy of a supposedly safe over 5 weeks post neutering op boar (not one of mine, I hasten to add); just to prove that particular point.
This will prevent him from pining and will also allow them to make friends through the bars (if they want to) and will take out a lot of the initial over-excitement in a mixed gender bonding and promote acceptance; especially if you have sows with fear-aggression issues.
In the end, it will still come down to to whether the the girls want him and if they can come to an agreement re. hierarchy. Sows past the natural ideal pup bearing age (ca. 3 years plus) are often much less accepting of a boar while younger sows very much have the biological urges pushing them towards acceptance.
Please take the time to read our very practical and informative step-by-step guide links in previous posts. You should find them very helpful. The bonding guide contains several videos and information on group bondings. 15 years of experience on this lively forum and owner experience of up to half a century have all gone into our guides.
You may also find this link here useful; what I am saying about mixed gender pairings largely also goes about group acceptance:
A Closer Look At Pairs (Boars - Sows - Mixed)
All the best! I am very fond of my neutered 'husboars' and have/have quite a number of them over the years. I currently have 6 of them, aged between 1-6 years.
