First the manufacture of the Rv is out of business. The maker of the slide rail is not, they are still in business.
If I were you, I would signup with these 2 yahoo Groups.
https://groups.yahoo.com/neo/groups/alfaseeya/info
https://groups.yahoo.com/neo/groups/SeeYaDP/info
We have one of the biggest support groups for Alfa Rv Motorhomes.
On the other hand if your brother is not a DIY'er then:
Leisure Coachworks in Fontana, Ca. (former workers of the Alfa MH)
Charlies Service in Sunset, Ut.
Another one in Bossier, La. for this one you need to join the Yahoo Groups.