As long as he has lots of hay available for him to eat and play in then it is fine.
Please do get him a friend though. I’m sorry you have been given poor advice from the place you got him from - he doesn’t and shouldn’t be kept by himself.
Bonding is a specific process which relies on compatibility. I’ve added some guides below to help
As he is a male, he will need a male friend which means your cage will need to be bigger than a Midwest. Two boars need 12 square feet of uninterrupted space.
Alternatively, have him neutered and then after the six week wait, look to find him a sow.
1 Introduction
2 Pre-bonding
- Quarantine and sexing
- The need for a plan B
- The rule-breaker: Youngsters under 4 months (sub-teenage)
3 Setting up an introduction
- Getting to know each other
- ‘Buddy baths’ – why not
- Scent swapping - why not
- Setting up a neutral bonding area
- How to start the bonding
4 Acceptance phase: Do we like...
1 Common myths and misconceptions
2 The different ages (including teenage)
- Important biological facts
- The formative 'School Weeks' (3 weeks - ca. 4 months)
- The Teenage Months (ca. 4-14 months)
- The Adult Years (ca. 15 months - ca. 4-5 years)
- The Golden Age (ca. 4-5 years until end of life)
3 What do boars need? (List of boar dos and don'ts)
- Space, space and more space!
- Respecting the hierarchy
- The 'one for each...
Introduction
1 When is a 'single' really a single?
- Bought singles
- Fallen-out and aggressive piggies
- Bereaved guinea pigs
- No interest in other guinea pigs
- Disabled and special needs guinea pigs
2 Companionship options (with pros and cons)
- Dating
- De-sexing (neutering or spaying)
- Living alongside
- Buying a baby companion
3 Caring for single guinea...