Unmarried partner - advise me please

I have been a studet for 6 years in the UK. I am planning to switch my visa to unmarried partner for my British partner. We were in Japan together 1994-1997 which can be proven by his old passport and some photos, etc. He left Japan in 1997 to come back to UK.

Then, I came here in 2001. We started living together in 2002. My concern is:

1. He got job seekers allowance 2002-2003. After this, he hasn't been working or hasn't got any benefit. However, I am working and can show sufficient funds in my bank statement. Also I can show some money transferred to his bank account from my bank account these 5 years. If my partner is not working, does it affect negatively on my application even if I can prove my financial situation is OK?

2. We have a lot of evidence around 2002-2004 (NHS, dentist, etc.),

but 2005, 06, 07, he can only show;

1. his mobile bills (almost every month, every year)
2. joint tenancy agreements every year.
3. Running event letter from council

This means he only has items from 3 sources instead of 5 which is the requirement. His bank statement is always registered in his mother's house. Also, as we pay gas, electricity and council tax bills to our landlord, we do not have any bills apart from BT. Our landlord will write a letter mentioning that most utility bills are addressed to him and the accommodation is adequate for a couple.
In my case I can show a lot of evidence. My side is OK, but his side of evidence is very small.. that's my concern.

3. We can show a lot of evidence about travelling abroad together and a social events we did together over many years.

I wonder if our long-term relationship and evidence of social events can cover the lack of his evidence of 2005-2007? I understand that the last 2 years evidence is the most important thing. I'd like to have everybody's opinion. Thanks.

Nezu wrote:He got job seekers allowance 2002-2003. After this, he hasn't been working or hasn't got any benefit.

If you don't mind may I ask, How has he been surviving all these years??

This is his source of income.

1. His mother is ill and he often looks after her. She gives some money from her pension.

2. I support him a bit as well

3. He did occasional work with which he earned about 2000 ponds a year. but he lost that job last summer.