Hi Jennifer,
This is a tricky one, as there aren't many resources available for it.
1. Contact the local St. Vincent chapter near him according to this zip-code sheet. Leave a voice message, and when they call explain their need and possible costs involved. These local groups can often be big helps for miscellaneous needs:
https://www.svdptacoma.org/svdp-helpline-zip-codes
2. Contact the OSLC Car Shop through Saviour Lutheran church. I am not sure if they help with RV's, but they might know other referrals:
https://oslc.com/carshop.html
3. Have client visit a few local repair shops and ask if he could clean their grounds at night, or work off a small repair in some way. Worth a shot.
4. Have client visit a few churches and offer the same help. May lead to something good.
Good luck, I know how this feels,
Tod