German Shepard mix fully shaved. Need advice.

He is approximately 15 and is a mix of a lot of breeds none of them particularly dominant. We say German Shepard mix because of his colouration but that's about as far as it goes.

I've just gotten my dog back from the vet hospital. Late Friday night I noticed he was struggling walking after having been playful that same morning without issue. As it was quite late I put him to bed and figured I'd take him to the vet in the morning. He was much worse in the morning. After calling around I finally got him in somewhere as an emergency consultation. The vet thought it was just his age and arthritis which he does have but the decline was so rapid I insisted it could be more. Turns out his tick prevention had lapsed and he had a dirty big one hiding under his collar. The vet changed his tune and removed it. We also found a second smaller one. He administered anti serum to treat the paralysis but they were closed over the weekend so i had to take him to the vet hospital in the city. Fixed up the bill and took him over and got him settled. They were pretty busy but said he'd be there at least a few days to watch for his breathing, swallowing etc. He made it through the weekend but wasn't good enough to come home yet so I picked him up and dropped him back at the vets who do weeknight care. While there they shaved him fully to check for more ticks. He had some proper food today and is walking again at about 50-60% of what he was so I could bring him home tonight (Wednesday).

The vet just said keep him calm and lots of small meals instead of big and give him a few weeks to recover fully.

Its mid spring here and still quite cool at times. Do I need to worry since he has hardly any coat left? What about going forwards, any particular things i should do or be aware of?

I know i should have asked more at the vets before leaving but I was admittedly too excited to see him walking and getting back to himself.