Bhishma is the Grand Sire of all Hindus.
He is so revered that Hindus perform the Tharpana, which is performed by one for his ancestors, for him though Bhishma never married for He wanted his father's offspring by his second wife to ascend the throne.
As he has done what is impossible for a Man( Being a Naishtika Mrahmachari, that is not allowing semen to fall ), Devavrata was rechristened Bhishma(one who does the impossible).
Lord Krishna has(d)the highest regard for Bhishma.
It was mutual.
During the Mahabharata War, as Bhishma lay dying, Krishna takes the Pandavas to Bhishma's Death bed and asks Bhishma to advise Yudhisthir on Dharma.
Bhishma says,
'Krishna, You are Dharma,
Why do you ask me to do this?
You can do it by yourself'
(Throughout the Mahabharata, Lord Krishna addresses Bhishma as 'Grandfather!)
Krishna replies.
'Dharma , when spoken by The One who has practiced, is strengthened"
This, mind you, from Krishna!
Let me paraphrase one essential sloka form Bhishma Stuti, Bhishma's prayer of Krishna as addressed to Duryodhana -Bhishma Parva 67/24)
'Vasudeva is is the Devata among all the Devatas.
He is the Embodiment of Dharma.
He fulfills everyone's desires.
He id the best among everyone.
He is the Creator.
He is the Action and its performer.
He is the Yagya, Yagya Performer and its results.
He is Lord unto Himself.
He is in the present, past and the Future.
He created Prajapathi(Fater of all).
He is the austerity of the Seers.
He is the Dawn, Dusk , the time when day Day meets Night and night meets the Day, Day and Night.
He is the Infinite.
He is also Finite.
He supports the World,Vishnu.
He is Brahman Rudra,
He is the Sadguna Brahman.
He is the Father.He is the parent of all.
He is Vamana and Narasimha.
He is the Grand sire of the Universe.
He is easily accessible.
He resides in the heart of the Seers, Hrishikesa.
In whom Krishna is pleased,he will get everything.
If one is afraid and takes refuge in Him, he need not Fear.
One who loves Krishna, will transcend desires.
The Bhishma Stuti.
