Hi there
I really! Recommend getting another piggie for Solly guinea pigs need to be in pairs or herds but since he is a boar he will need either another boar or getting him fixed and adopting a sow, they can get quite depressed without a companion even if you spend all the time in the world with them it’s not the same as having another piggie friend to interact with
If you can adopt another boar check if there are any rescues around so you can do dating it’s when you bring your piggie and see if they get along with another piggie and if they do you can adopt them, but you will need to edit your cage if it’s too small for two piggies, if you adopt another boar them you would look at around 2 metres long and a metre wide
And with his food if he is looking a bit poorly best take him too the vet better safe then sorry